JP2009174409A - Pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump device certainly started with low starting current. <P>SOLUTION: This pump device includes a plurality of pumps 1 arranged in a suction sump 20, and a control section 10 controlling operation of the plurality of pumps 1. Each of the plurality of pumps 1 has an impeller transferring water, and an electric motor 3 rotating the impeller. The control section 10 is operated in order to reduce the rotational speed of the electric motor 3 of the pump during operation or the blade angle of the impeller before at least the last one of the plurality of pumps 1 is started. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pump device, and more particularly, to a motor-driven pump device that can reduce a transient current required when starting the pump device.

  A pump device that uses an electric motor as a drive source is generally operated by receiving electric power from an electric power company (electric power system) or a private generator. When power is supplied from an electric power company, if an excessive load is applied instantaneously, a power failure may occur due to an instantaneous voltage drop, which may adversely affect other customers using the power system. is there. For this reason, electric power companies may place restrictions on inrush current and voltage drop.

  When starting the pump device under such a situation, the starting current (transient current) may exceed the limit current in a so-called direct-injection starting method in which the electric power from the power system is directly applied to the motor. is there. Therefore, a starting method such as reduced voltage starting, inverter starting, or secondary resistance starting, which can suppress the starting current while generating a high torque sufficient to start the pump in the electric motor, is employed. However, such a starting method requires an expensive starting device and an electric motor, and causes an increase in cost. Further, since the structure of the starter is complicated, the reliability of the pump device is also lowered.

  Even when electric power is supplied by a private generator such as a gas turbine generator or a diesel engine generator, if a large load is applied to the generator when the pump device is started, the generator is stopped due to an instantaneous voltage drop. For this reason, it is common to use a generator having a sufficient capacity for the starting current of the pump device. However, a large-capacity generator is costly and is not cost effective because a generator having a capacity larger than that required during rated operation of the pump device must be provided.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a pump device that can suppress a transient current at the start of the pump and can start the pump reliably.

  In order to achieve the above-described object, one aspect of the present invention is a pump device including a plurality of pumps arranged in a suction water tank and a control unit that controls operation of the plurality of pumps. Each of the pumps includes an impeller that transfers water, an electric motor that rotates the impeller, and a transmission that changes a rotation speed of the electric motor, and the control unit includes at least one of the plurality of pumps. Before starting the last one, the rotational speed of the electric motor of the pump in operation is reduced via the transmission.

  Another aspect of the present invention is a pump device including a plurality of pumps disposed in a suction water tank and a control unit that controls operation of the plurality of pumps, wherein each of the plurality of pumps supplies water. An impeller to be transferred, an electric motor that rotates the impeller, and a blade angle variable mechanism that changes a blade angle of the impeller, and the control unit includes at least the last one of the plurality of pumps. Before starting, the blade angle of the pump in operation is reduced through the blade angle variable mechanism.

  Another aspect of the present invention is a pump device including a plurality of pumps arranged in a suction water tank, a control unit that controls operation of the plurality of pumps, and a water level detector that detects a water level of the suction water tank. Each of the plurality of pumps includes an impeller for transferring water and an electric motor for rotating the impeller, and the control unit is configured to generate the suction water tank based on a signal from the water level detector. The plurality of pumps are sequentially started as the water level rises, and at least the last pump to be started among the plurality of pumps is a pump having a specific speed greater than 900.

  Another aspect of the present invention is a pump device including a plurality of pumps disposed in a suction water tank and a control unit that controls operation of the plurality of pumps, wherein each of the plurality of pumps supplies water. An impeller to be transferred, an electric motor for rotating the impeller, and a discharge valve for adjusting a discharge amount of the pump, and the plurality of pumps are pumps having a specific speed of 900 or less, The control unit is characterized in that before starting at least the last one of the plurality of pumps, the discharge valve of the pump in operation is closed to operate the pump below the rated discharge amount.

  Another aspect of the present invention is a pump device including a plurality of pumps disposed in a suction water tank and a control unit that controls operation of the plurality of pumps, wherein each of the plurality of pumps supplies water. An impeller for transferring and an electric motor for rotating the impeller, wherein one of the plurality of pumps is a pump having a smaller electric motor output than the other pumps, and the control unit includes the electric motor It is characterized by starting the pump with a small output last.

  Another aspect of the present invention is a pump device including a plurality of pumps disposed in a suction water tank and a control unit that controls operation of the plurality of pumps, wherein each of the plurality of pumps supplies water. A moving impeller, an electric motor for rotating the impeller, a casing for housing the impeller, a siphon forming pipe connected to a discharge port of the casing, and a siphon breaker provided at the top of the siphon forming pipe Each of the plurality of pumps is a pump having a specific speed of 900 or less, and the control unit is configured to switch the pumps in operation before starting at least the last one of the plurality of pumps. The siphon breaker is operated to destroy the siphon formed in the siphon forming pipe.

  Another aspect of the present invention is a pump device including a pump disposed in a suction water tank and a control unit that controls the operation of the pump, the pump including an impeller for transferring water, and the blade An electric motor for rotating the vehicle; a starter having a reactor disposed between the electric motor and a power source; and an auxiliary electric motor coupled to a drive shaft of the electric motor, wherein the control unit includes the reactor The starting device is operated so as to start the motor by supplying a current from the power source through the power source, then the auxiliary motor is started, and then the current is directly supplied from the power source to the motor without passing through the reactor. The starter is operated to supply, and then the auxiliary motor is stopped.

  In a preferred aspect of the present invention, the pump device further includes a storage battery for supplying a direct current to the auxiliary motor, and the auxiliary motor is a DC motor.

  According to the present invention, the pump device can be reliably started with a low starting current. Therefore, even if the current supplied from the power system is limited, the pump device can be started without the start current exceeding the limited current. Moreover, the capacity | capacitance of private generators, such as a gas turbine generator and a diesel engine generator, can be made small.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a side view showing a pump device according to the first embodiment of the present invention, and FIG. 2 is a plan view of the pump device of FIG.

  As shown in FIGS. 1 and 2, this pump device includes two pumps 1, 1 and a control unit 10 that controls the operation of the pumps 1, 1. These pumps 1, 1 are arranged in parallel in the suction water tank 20. In addition, in the example shown in FIG. 2, although the pump apparatus provided with the two pumps 1 and 1 is shown, this invention is not restricted to this structure, You may provide three or more pumps.

  As shown in FIG. 1, each pump 1 includes an impeller 2 that transfers water, an electric motor 3 that rotates the impeller 2, an inverter device (transmission device) 7 that changes the rotational speed of the electric motor 3, and an electric motor 3. And the impeller 2, a casing 4 that houses the impeller 2, and a discharge valve 5 that is provided at the discharge port of the casing 4. The suction port of the pump 1 is submerged in the water in the suction water tank 20. The suction water tank 20 is connected to a river or a water channel (not shown) so that water flows into the suction water tank 20. The suction water tank 20 is provided with a water level detector 6 for detecting the water level. The control unit 10 is connected to the water level detector 6, the actuator (not shown) of the discharge valve 5, and the inverter device 7.

  When the impeller 2 is rotated by the electric motor 3, the water in the suction water tank 20 is sucked up from the suction port and transferred to the discharge side through the casing 4 and the discharge pipe 11. The above-described discharge valve 5 is provided between the discharge port of the casing 4 and the discharge pipe 11 so that the discharge valve 5 can open and close or adjust the flow rate (discharge amount) of water. It has become. The control unit 10 is configured to control the discharge valve 5, the rotation speed of the electric motor 3, and the like. The type of the pump 1 is not limited to the vertical axis type, and a horizontal axis type, an oblique axis type, a spiral type, an underwater type, or the like can be used.

  The inverter device 7 is configured to change the rotation speed of the electric motor 3 based on a command signal from the control unit 10. Therefore, the discharge amount can be changed by changing the rotation speed of the electric motor 3. Also, the discharge amount can be changed by operating the discharge valve 5 described above.

  FIG. 3A is a diagram showing a characteristic curve when the rotation speed of the electric motor 3 is changed. Curves N1 and N2 indicate characteristic curves of the pump 1 at rotational speeds n1 and n2 (n1> n2), respectively. A curve R is a resistance curve indicating a pipe loss according to the flow rate of water from the pump 1 to the terminal outlet (discharge port) of the discharge pipe 11. A curve E1 is a characteristic curve showing a relationship between the power consumption of the motor 3 and the discharge amount when the rotation speed of the motor 3 is n1. Similarly, the curve E2 is a characteristic curve showing the relationship between the power consumption of the motor 3 and the discharge amount when the rotation speed of the motor 3 is n2.

  In FIG. 3A, the operating point of the pump 1 at the rotational speed n1 is a point A1. When the rotation speed of the electric motor 3 is decreased from n1 to n2, the operating point moves on the resistance curve R from the point A1 to the point A2. At this time, the power consumption of the electric motor 3 also decreases from B1 to B2. This means that the load applied to the electric motor 3 is reduced, and the current to be supplied to the electric motor 3 may be small.

  In the graph shown in FIG. 3A, it is shown that the load on the electric motor 3 is reduced by lowering the rotation speed of the electric motor 3, but instead of the rotation speed of the electric motor 3, the blade angle of the impeller 2 is changed. Changing the load can also reduce the load. A characteristic curve when the blade angle of the impeller 2 is changed is shown in FIG. Curves C1 and C2 in FIG. 3B show characteristic curves of the pump 1 at blade angles c1 and c2 (c1> c2), respectively, and the curves F1 and F2 indicate the discharge amount at the blade angles c1 and c2, respectively. It shows the relationship with power consumption. As can be seen from FIG. 3 (b), the operating point can be lowered by changing the blade angle, thereby reducing the current required for the electric motor 3. In this case, the blades of the impeller 2 are operated by an actuator (blade angle variable mechanism) (not shown), and the blade angle is changed based on a command signal from the control unit 10.

Next, a method for starting the pump device will be described in detail. FIG. 4 is a control diagram showing a starting method of the pump device according to the first embodiment of the present invention.
As shown in FIG. 4, upon receiving a pump start command, the control unit 10 determines whether or not the pump to be started next is the last pump. If the next pump to be started is not the last pump, start the pump normally. On the other hand, when the pump to be started next is the last pump, the rotational speed of the electric motor 3 that drives the pump is reduced or the pump is reduced in order to reduce the load on the electric motor 3 of the operating pump. The blade angle of the impeller 2 is reduced. One pump or a plurality of pumps to be operated at a low load may be used, and are appropriately determined according to the specifications of the pump device.

  After such a load reduction operation is completed, the next pump (ie, the last pump) is started. When the start of the last pump is completed, the pump operating at a low load is returned to the normal operation. That is, the rotational speed of the electric motor 3 operating at a low load or the blade angle of the impeller is returned to the normal state. Thereafter, all pumps are rated.

  Next, a change in current when the pump device is started will be described in comparison with a conventional starting method. FIG. 5 is a graph showing a change in current when the pump device is started according to the conventional start method, and FIG. 6 is a graph showing a change in current when the pump device is started according to the start method according to the present embodiment. . 5 and 6 show an example of a pump device including three pumps.

  As shown in FIG. 5, when starting the first pump, the second pump, and the third pump (the last pump), a starting current (transient current) flows to the electric motor. The load (current) applied to the power supply increases each time the pump is started, and becomes the largest at the last pump start. Such a change in current is the same in the present embodiment shown in FIG.

  In this embodiment, as shown in FIG. 6, the load on the operating pump (the first pump and / or the second pump) is reduced before the third pump (the last pump) is started. The operation is performed, whereby the current is lowered from the current during the rated operation (see time T1). Since the third pump (the last pump) is started in this state, the current supplied to the entire pump device when the third pump starts is lower than that in the conventional example shown in FIG. . After the start operation of the third pump is completed, the pump (the first pump and / or the second pump) that has been operated at a low load is returned to the rated operation (see time T2), thereby the pump device The whole is rated.

  Thus, according to this embodiment, since the load of the pump in operation is reduced before starting the last pump, the current (pump operation and Current required for starting) can be reduced. Therefore, even when there is a limit on the power supplied from the power system, the pump device can be reliably started without exceeding the limit value, and the power supply source such as the power system and the generator Can prevent an instantaneous voltage drop.

  Moreover, when using private generators, such as a gas turbine generator and a diesel engine generator, as a power supply of a pump apparatus, the capacity | capacitance of this private generator can be made small. The capacity of the private generator is generally (1) power required for steady operation of the pump device, (2) power supply capacity sufficiently large with respect to the maximum voltage drop at the start of the pump device, and (3) start of the pump device. It is determined from the maximum value among the three items of the maximum short-time withstand capability at the time.

  Among these, the item (3) is obtained by adding the steady load of the pump being operated to the capacity (starting current) required at the time of starting the last pump. Therefore, suppressing the steady load (current during steady operation) of the pump during operation leads to a reduction in the capacity of the private generator. According to this embodiment, the capacity of the private generator can be reduced, and the cost of the drainage station including the pump device and the generator can be reduced.

  Here, it is preferable to employ a pump having a specific speed greater than 900 as at least the last pump to be started. The reason is as follows. As shown in FIG. 7, the pump device having a plurality of pumps is configured to sequentially start the pumps as the water level of the suction water tank rises. On the other hand, the discharge-side river is often a large-capacity river, and the discharge-side water level is almost constant with little change. Therefore, the actual lift (H2) at the start of the second pump is smaller than the actual lift (H1) at the start of the first pump, and the actual lift (Hm) at the start of the last pump is smaller. Smallest.

  In general, a pump having a specific speed greater than 900 has an operation characteristic that the shaft power decreases as the actual head decreases. That is, when the actual head is reduced and the operating point of the pump is changed to the excessive flow rate side, the shaft power of the pump is reduced. Therefore, when a pump having a specific speed greater than 900 is used for the last pump, preferably all pumps, the shaft power at the time of starting can be reduced. In this case, it is not necessary to control the rotation speed or blade angle of the electric motor 3 as described above.

  In addition, although this embodiment shows the example which lowers the transient current at the time of the start of the last pump, the transient current in the pump of the last unit of the last unit becomes a problem by the specification of the pump device and the condition of the power system. In this case, the control unit 10 may determine whether or not the pump to be started next is the pump preceding the last unit and perform similar load reduction control. Furthermore, similar load reduction control may be performed when a plurality of pumps including the last pump are started.

  Next, a second embodiment of the present invention will be described. Note that the configuration of the present embodiment that is not particularly described is the same as that of the first embodiment described above, and thus redundant description thereof is omitted.

  In the present embodiment, instead of changing the rotation speed of the electric motor 3 or the blade angle of the impeller 2, the load on the pump 1 is reduced by operating the discharge valve 5 to change the discharge amount. It is different from the embodiment. In the present embodiment, each pump 1 uses a pump having a specific speed of 900 or less. A pump with a specific speed of 900 or less shows a characteristic curve in which shaft power increases as the discharge rate increases.

  FIG. 8 is a diagram showing a characteristic curve of a pump having a specific speed of about 400 as an example of a pump having a specific speed of 900 or less. Under the condition where the rotation speed of the electric motor (impeller) is constant, as shown in FIG. 8, the total lift becomes lower as the discharge amount increases. Further, as the discharge amount increases, the shaft power increases. Therefore, it can be seen from FIG. 8 that the shaft power decreases as the discharge amount decreases, that is, the total lift increases. The shaft power means power necessary to rotate the rotating shaft of the impeller.

  FIG. 9 is a graph showing a resistance curve that changes depending on the opening / closing operation of the discharge valve 5. In FIG. 9, a curve N1 indicates a characteristic curve of the pump 1 at the rotational speed n1. A curve R1 is a resistance curve showing a line loss according to the flow rate of water from the pump 1 to the end outlet of the discharge pipe 11 when the discharge valve 5 is opened. A curve R2 is a resistance curve when the discharge valve 5 is closed and the discharge amount is lowered. A curve S1 is a characteristic curve showing the relationship between the shaft power and the discharge amount when the rotation speed of the electric motor 3 is n1.

  The operating point of the pump 1 when the discharge valve 5 is fully open is the point A1. When the discharge valve 5 is closed to lower the discharge amount, the operating point moves from the point A1 to the point A2 on the characteristic curve N1. At this time, the shaft power also decreases from C1 to C2. Therefore, similarly to the case where the rotation speed of the electric motor 3 is lowered, the load applied to the electric motor 3 is reduced, and the current to be supplied to the electric motor 3 can be reduced. The graph shown in FIG. 9 shows an example in which the discharge valve 5 is closed to reduce the discharge amount, but the discharge valve 5 is completely closed (that is, in a closed state) and the discharge amount is set to 0. It is good.

Next, the starting method according to the present embodiment will be described with reference to FIG. FIG. 10 is a control diagram showing a starting method of the pump device according to the second embodiment of the present invention.
As shown in FIG. 10, upon receiving a pump start command, the control unit 10 determines whether or not the pump to be started next is the last pump. If the next pump to be started is not the last pump, start the pump normally.

  On the other hand, when the pump to be started next is the last pump, the discharge valve 5 of the pump in operation is closed to reduce the discharge amount of the pump. In this case, the discharge valve 5 may be completely closed and the discharge amount may be zero. One discharge valve 5 may be closed or a plurality of discharge valves 5 may be closed. After the operation of the discharge valve 5 is completed, the next pump (that is, the last pump) is started. When the start of the last pump is completed, the discharge valve 5 is opened and all the pumps are rated. In this way, the current flowing through the pump in operation can be reduced by operating the pump having a specific speed of 900 or less or the small water amount operation or the shut-off operation.

Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the structure same as 1st Embodiment mentioned above, and the overlapping description is abbreviate | omitted.
FIG. 11 is a plan view showing a pump device according to the third embodiment of the present invention. 12 is a side view of the pump device shown in FIG. 11, and FIG. 13 is the other side view of the pump device shown in FIG. In this embodiment, a private generator such as a gas turbine generator or a diesel engine generator is used as a power source for the pump device.

  As shown in FIGS. 11 to 13, this pump device includes two pumps (a large capacity pump 1 </ b> A and a small capacity pump 1 </ b> B) having different sizes (capacity, that is, the output of the electric motor 3). The basic configurations of the pumps 1A and 1B are the same as each other, and each includes an impeller (not shown), an electric motor (submersible motor) 3, a casing 4, and a discharge valve 5. In this embodiment, two pumps 1A and 1B are arranged, but three or more pumps may be provided. In this case, at least one of the plurality of pumps becomes a small capacity pump.

  In this embodiment, the small capacity pump 1B is started last. FIG. 14 is a control diagram showing a starting method of the pump device of this embodiment. As shown in FIG. 14, upon receiving a pump start command, the control unit 10 determines whether or not the pump to be started next is the last pump. If the next pump to be started is not the last pump, start the pump normally.

  On the other hand, when the pump to be started next is the last pump, the control unit 10 determines whether or not the pump to be started next is the small capacity pump 1B. When the last pump is the small capacity pump 1B, the small capacity pump 1B is started. On the other hand, when the last pump is not the small capacity pump 1B, the small capacity pump 1B in operation is stopped. After the stop operation of the small capacity pump 1B is completed, the pump to be started next (large capacity pump 1A) is started. Then, after the start of the large capacity pump 1A is completed, the small capacity pump 1B is started. When there are three or more pumps, the pump whose capacity is not maximum (preferably the pump having the minimum capacity) is the pump that is started last.

  As described above, the maximum short-time withstand capability at the time of starting the pump device, which is one of the factors that determine the capacity of the generator, is the capacity (starting current) required at the time of the last pump start, It is calculated by adding a steady load of. Therefore, suppressing the steady load (current during steady operation) of the pump during operation leads to a reduction in the capacity of the private generator. According to the starting method according to the present embodiment, by starting the small capacity pump with a small starting current last, the capacity of the private generator can be reduced, and an inexpensive drainage station can be obtained.

Next, a fourth embodiment of the present invention will be described.
FIG. 15 is a cross-sectional view showing a pump device according to a fourth embodiment of the present invention. The pump apparatus according to this embodiment includes a plurality of pumps 1 shown in FIG. Each pump 1 includes an impeller 2, an electric motor 3 that rotates the impeller 2, a rotating shaft 12 that connects the impeller 2 and the electric motor 3, a casing 4 that houses the impeller 2 and the rotating shaft 12, A siphon forming pipe 14 connected to the discharge port of the casing 4 and extending through a point higher than the highest water level on the discharge side. The suction port of the pump 1 is located in the suction water tank.

  The siphon forming pipe 14 is for transferring water from the suction side to the discharge side using the principle of the siphon. A siphon breaker 15 is provided on the top of the siphon forming pipe 14. In the present embodiment, a vertical shaft pump is employed as the pump 1, but the present invention is not limited to this, and various pumps such as a horizontal shaft type, an oblique shaft type, a spiral type, and an underwater type can be used. .

  As for the pump 1 which concerns on this embodiment, the pump whose specific speed is 900 or less is used for all. As described with reference to FIG. 8, a pump having a specific speed of 900 or less has a characteristic that the shaft power decreases as the discharge amount decreases or the total lift increases. In the present embodiment, the load applied to the electric motor 3 is reduced using this operation characteristic. Specifically, before starting the last pump, the siphon breaker 15 of the pump in operation is operated to destroy the siphon formed in the siphon forming pipe 14. As a result, as shown in FIG. 15, the actual head is temporarily increased to lower the shaft power.

  As the siphon breaker 15, a mechanism including a valve and an actuator for operating the valve is employed. When the siphon breaker 15 is opened, air enters the siphon forming pipe 14 through the siphon breaker 15, thereby destroying the siphon formed in the siphon forming pipe 14. When forming the siphon, the siphon breaker 15 is closed, the inflow of air into the siphon forming pipe 14 is shut off, and the siphon is formed by the self siphon by the discharge water flow of the pump 1. Note that the siphon breaker 15 is operated by a command signal from the control unit 10.

  A method for starting the pump device according to the present embodiment will be described in detail with reference to FIG. As shown in FIG. 16, upon receiving a pump start command, the control unit 10 determines whether or not the pump to be started next is the last pump. If the next pump to be started is not the last pump, start the pump normally. On the other hand, when the pump to be started next is the last pump, the siphon breaker 15 of the pump is operated (opened) to reduce the load on the motor 3 of the pump in operation, and the siphon formation is performed. The siphon formed in the pipe 14 is destroyed. In addition, the pump by which a siphon is destroyed may be 1 unit | set, or multiple units | sets may be determined suitably by the specification of the pump apparatus.

  After siphon destruction is complete, the next pump (ie, the last pump) is started. When the start of the last pump is completed, the siphon breaker 15 is operated (closed), and the siphon is formed again in the siphon forming pipe 14. Thereafter, all pumps are rated.

  As shown in FIG. 15, when the siphon formed in the siphon forming pipe 14 is destroyed, the actual lifting height increases. Therefore, in a pump with a specific speed of 900 or less, the shaft power required for the operation of the pump decreases, and as a result, the current to be supplied to the electric motor 3 also decreases. Therefore, similarly to the above-described embodiment, the transient current required at the time of starting the last pump can be reduced.

Next, a fifth embodiment of the present invention will be described.
FIG. 17 is a cross-sectional view illustrating a pump device according to a fifth embodiment of the present invention. The pump device according to the present embodiment includes one pump 1 and a control unit 10. However, a plurality of pumps may be provided as in the embodiment described above. As shown in FIG. 17, the pump 1 accommodates an impeller 2, an electric motor 3 that rotates the impeller 2, a rotary shaft 12 that connects the impeller 2 and the electric motor 3, an impeller 2, and the rotary shaft 12. Casing 4, a starting device 17 having a reactor (not shown), and an auxiliary electric motor 18 connected to the drive shaft of the electric motor 3. The suction port of the pump 1 is located in the suction water tank, and the discharge port of the pump 1 is located in the discharge side water tank.

  The starter 17 is disposed between the power source (power system or private generator) and the motor 3, and the current from the power source is supplied to the motor 3 through the starter 17. The starter 17 has a reactor (not shown) arranged in series with the electric motor 3, switches the current path so as to bypass the reactor after the pump is started, and supplies the electric current from the power source directly to the electric motor 3. To work. According to such a starting device 17, a large starting torque can be obtained with a smaller current.

  However, depending on the specifications of the pump, there are cases where the reactor cannot be started with a reactor-type starter. In such a case, a condorfa type starter has been conventionally used. This condorfa type starter is a V-connection single-turn transformer and has a feature that it can generate a starting torque larger than that of a reactor type starter.

  FIG. 18 is a graph showing the relationship between the rotational speed and torque of the electric motor, and shows a conventional starting method. In FIG. 18, the left area of the dotted line extending vertically is an area where the starting current is outside the allowable range when the power source and the motor are directly connected (that is, the area exceeding the limit value from the electric power company), and the right area of the dotted line is In this region, even if the power source and the motor are directly connected, the starting current is within the allowable range.

  In the conventional starting method, first, the starting of the electric motor is started by using a condorfa type starting device (automatic transformer). When the rotational speed of the motor increases and the starting current falls within the allowable range, the current path is switched to short-circuit the autotransformer and the power supply is directly connected to the motor. In FIG. 18, the current path switching point SW is a point where the torque of the electric motor supplied with the current through the autotransformer and the torque necessary for driving the pump substantially coincide. After switching, the pump is operated in a state where current is directly supplied from the power source to the electric motor without going through the autotransformer.

  On the other hand, in the reactor starting method, depending on the specifications of the pump, as shown in FIG. 18, it may not be possible to increase the speed of the motor to a rotational speed at which the starting current of the motor becomes small. In such a case, in a conventional pump device, a condorfa starting method using a condorfa-type starting device (automatic transformer) has been adopted. However, the condorfa type starter has the advantage of being able to generate a large starting torque with a small starting current, but has the disadvantage that it is more expensive than the reactor type starter.

  Therefore, in the present embodiment, an auxiliary electric motor 18 that assists the electric motor 3 is provided in order to increase the starting torque while adopting an inexpensive reactor-type starting device 17. FIG. 19 is a graph showing the relationship between the rotational speed and torque of the electric motor 3 in the pump device according to the present embodiment. As shown in FIG. 19, the auxiliary motor 18 is driven after starting the electric motor 3 through the reactor type starter 17. After the rotational speed of the electric motor 3 is increased and the starting current is within an allowable range, the starting device is in a state where the total torque of the auxiliary electric motor 18 and the electric motor 3 exceeds the torque required for driving the pump 1. Short-circuit the 17 reactors. Thereby, the current from the power source is directly supplied to the electric motor 3 without passing through the reactor. Thereafter, the auxiliary electric motor 18 is stopped, and the electric motor 3 directly receives the current from the power source and drives the pump 1. Such a starting sequence is controlled by the control unit 10.

  Since this auxiliary motor 18 is used only at the time of starting, it is not necessary to use an expensive continuously rated motor as the auxiliary motor 18, and an inexpensive short-time rated motor can be used. The auxiliary motor 18 may have a smaller capacity than the electric motor 3. Therefore, according to the present embodiment, it is possible to provide a pump device that can reduce the transient current required at the time of starting at low cost.

  In addition, when providing the some pump 1, as shown in FIG. 20, the adjacent electric motors 3 may be connected by the clutch mechanism 24, and the electric motor 3 of the pump 1 in operation may be used as an auxiliary electric motor. Further, as shown in FIG. 21, a water wheel 25 and a small pump 26 may be connected to the electric motor 3 and the auxiliary electric motor 18, respectively, and the water wheel 25 and the small pump 26 may be connected using water as a medium.

  FIG. 22 is a diagram illustrating another configuration example of the present embodiment. In this example, a DC motor 27 is used as an auxiliary motor, and a storage battery 28 as a DC power source is connected to the DC motor 27. According to such a configuration, the load on the power source (power system or generator) for driving the electric motor 3 is reduced, and troubles such as an instantaneous voltage drop can be reliably avoided. Moreover, the pump device can be started more safely by employing the DC motor 27 having a large torque at startup as the auxiliary motor.

  The above-described embodiments have been described so that those skilled in the art can implement the present invention. Therefore, the present invention is not limited to the above-described embodiments, but should be defined by the widest scope of technical ideas described in the claims.

It is a side view which shows a pump apparatus. It is a top view of the pump apparatus of FIG. FIG. 3A is a diagram showing a characteristic curve when the rotation speed of the electric motor is changed, and FIG. 3B is a diagram showing a characteristic curve when the blade angle of the impeller is changed. It is a control diagram which shows the starting method of the pump apparatus which concerns on the 1st Embodiment of this invention. It is a graph which shows the change of an electric current when a pump apparatus is started according to the conventional starting method. It is a graph which shows the change of an electric current when the pump apparatus is started according to the starting method which concerns on 1st Embodiment. It is a figure for demonstrating the relationship between the water level of a suction tank, and an actual head. It is a figure which shows the characteristic curve of the pump whose specific speed is about 400. It is a graph which shows the resistance curve which changes with opening / closing operation | movement of a discharge valve. It is a control diagram which shows the starting method of the pump apparatus which concerns on the 2nd Embodiment of this invention. It is a top view which shows the pump apparatus which concerns on the 3rd Embodiment of this invention. It is one side view of the pump apparatus shown in FIG. It is the other side view of the pump apparatus shown in FIG. It is a control diagram which shows the starting method of the pump apparatus which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the pump apparatus which concerns on the 4th Embodiment of this invention. It is a control diagram which shows the starting method of the pump apparatus which concerns on the 4th Embodiment of this invention. It is sectional drawing which shows the pump apparatus which concerns on the 5th Embodiment of this invention. It is a graph which shows the relationship between the rotational speed of an electric motor, and a torque, and shows the conventional starting method. It is a graph which shows the relationship between the rotational speed of an electric motor, and a torque in the pump apparatus which concerns on the 5th Embodiment of this invention. It is a figure which shows a part of modification of the pump apparatus which concerns on the 5th Embodiment of this invention. It is a figure which shows a part of other modification of the pump apparatus which concerns on the 5th Embodiment of this invention. It is sectional drawing which shows the further another modification of the pump apparatus which concerns on the 5th Embodiment of this invention.

Explanation of symbols

1, 1A, 1B Pump 2 Impeller 3 Electric motor 4 Casing 5 Discharge valve 6 Water level detector 7 Inverter device (transmission device)
DESCRIPTION OF SYMBOLS 10 Control part 11 Discharge pipe 12 Rotating shaft 14 Siphon formation piping 15 Siphon breaker 17 Starter 18 Auxiliary motor 20 Water supply water tank 24 Clutch mechanism 25 Water wheel 26 Small pump 27 DC motor (auxiliary motor)
28 battery

Claims (8)

A plurality of pumps arranged in the suction tank,
A pump device comprising a controller for controlling the operation of the plurality of pumps,
Each of the plurality of pumps is
An impeller for transferring water;
An electric motor for rotating the impeller;
A transmission for changing the rotation speed of the electric motor,
The said control part reduces the rotational speed of the said motor of the pump in operation via the said transmission before starting at least the last one of these pumps. A plurality of pumps arranged in the suction tank,
A pump device comprising a controller for controlling the operation of the plurality of pumps,
Each of the plurality of pumps is
An impeller for transferring water;
An electric motor for rotating the impeller;
A blade angle variable mechanism that changes the blade angle of the impeller,
The said control part makes the said blade angle of the pump in operation small through the said blade angle variable mechanism, before starting at least the last one of these pumps. A plurality of pumps arranged in the suction tank,
A control unit for controlling operation of the plurality of pumps;
A pump device comprising a water level detector for detecting the water level of the suction water tank,
Each of the plurality of pumps includes an impeller that transfers water and an electric motor that rotates the impeller.
The control unit, based on a signal from the water level detector, sequentially starts the plurality of pumps according to a rise in the water level of the suction water tank,
The pump device characterized in that the pump that is started at least last among the plurality of pumps is a pump having a specific speed greater than 900. A plurality of pumps arranged in the suction tank,
A pump device comprising a controller for controlling the operation of the plurality of pumps,
Each of the plurality of pumps is
An impeller for transferring water;
An electric motor for rotating the impeller;
A discharge valve for adjusting the discharge amount of the pump,
The plurality of pumps are all pumps having a specific speed of 900 or less,
The control unit closes the discharge valve of the pump in operation before starting at least the last one of the plurality of pumps, and operates the pump with less than a rated discharge amount. . A plurality of pumps arranged in the suction tank,
A pump device comprising a controller for controlling the operation of the plurality of pumps,
Each of the plurality of pumps includes an impeller that transfers water and an electric motor that rotates the impeller.
One of the plurality of pumps is a pump having a smaller motor output than the other pumps,
The said control part starts the pump with a small said motor output last, The pump apparatus characterized by the above-mentioned. A plurality of pumps arranged in the suction tank,
A pump device comprising a controller for controlling the operation of the plurality of pumps,
Each of the plurality of pumps is
An impeller for transferring water;
An electric motor for rotating the impeller;
A casing for housing the impeller,
A siphon forming pipe connected to the discharge port of the casing;
A siphon breaker provided at the top of the siphon forming pipe,
The plurality of pumps are all pumps having a specific speed of 900 or less,
The control unit operates to operate the siphon breaker of the pump in operation and destroy the siphon formed in the siphon forming pipe before starting at least the last one of the plurality of pumps. A pump device characterized. A pump arranged in the suction tank,
A pump device comprising a control unit for controlling the operation of the pump,
The pump is
An impeller for transferring water;
An electric motor for rotating the impeller;
A starter having a reactor, disposed between the motor and a power source;
An auxiliary motor coupled to the drive shaft of the motor,
The control unit operates the starter so as to start the motor by supplying a current from the power source to the motor via the reactor, and then starts the auxiliary motor, and then starts the auxiliary motor without passing through the reactor. The pump device is characterized in that the starting device is operated so as to supply current directly to the electric motor, and then the auxiliary electric motor is stopped. The pump device further includes a storage battery for supplying a direct current to the auxiliary motor,
The pump device according to claim 7, wherein the auxiliary motor is a DC motor.

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