DE2756459A1 - CONTROL SWITCH DEVICE - Google Patents

Description

_ ₉ _ 2755459

Power Management Corporation 65 West Park Road, Centerville, Ohio 45459 / USA

The invention relates to a power contact device for controlling the application of power to a load, such as z. B. an electric motor or a heater.

Known control contact devices or control contactors often have two groups of power contactors, one group each for one direction of rotation of the motor. Since arcing occurs over every contactor or control contactor devices are normally provided to protect the contacts. For example, a contactor on a three-phase motor has three power contacts that close to the motor rotating in a forward direction, and three additional contacts that close to the motor in the opposite Rotate direction requires a total of six arc suppressors to properly protect the contacts.

The present invention relates to a power contactor for control of current and characteristics of an electric current to a load and relates in particular to

L-jitt K 3't'i hl

'/ 809826/0777

in particular, a contactor that is inexpensive and requires a minimum of arc suppression circuitry.

According to the invention, a single load relay is used to apply and remove a force or power to or from a load, such as. An electric motor or heater, and a control or steering relay is used to control the nature of the current to the load, e.g. B. the current direction to the motor or the voltage to the heater. Control circuit means are used according to the invention to ensure that the contacts of the steering relay does not ° ff _NEN or close, while the current is at the load, and therefore according to the invention arc suppression means via the contacts of the steering relay unnecessary. Consequently, according to the invention, arc suppression devices are only provided for the power relay contactors, which reduces the overall cost of the control unit.

In a preferred embodiment of the invention, the Force or power applied to the load through normally closed contacts of the steering relay or control relay, and the power relay is directly supplied with energy or excited. If desired, the type or characteristic of the To change the current, d. H. i.e. to reverse the direction of rotation of the motor or to increase the temperature of the heating device, the power relay is energized through a group of normally open contacts on the control relay, ensuring becomes that the control relay has been energized and those

B09B? 6/0777

Contacts connected to the load have been closed before the contacts of the power relay are closed. The control relay circuit is provided with a time delay device, which after switching off of the load cause the control relay to remain energized long enough for the power relay contacts to close can open. Therefore, the contacts of the control relay are always in their desired position during application and the decrease in power or power on or from the load, and therefore arc suppressors are only necessary across the contacts of the power relay.

The arc suppressors used in the preferred embodiment of the invention are similar to those shown in U.S. Patent 3,982,137. after which an auxiliary contact, which is assigned to each contact of the power relay, is used to supply the control current to a solid state device connected in parallel to the main contactors. The auxiliary contacts are designed so that they close immediately either before closing or opening the main contacts and themselves open immediately after either closing or opening the main contacts to provide control current to the solid state device, thereby reducing the voltage across the main contact and preventing arcing, while the contact is being opened or closed, and to remove the control current when the contacts are closed to protect and protect the solid-state device

809826/0777

prevent it from continuously carrying current if the main contacts do not close properly or with significant resistance close in between.

The object of the invention is therefore to provide an improved and inexpensive control circuit of the type described for controlling the application of an electric current to a load using a minimum number of arc suppression devices, and in particular a power consumption control circuit for an electrical load with a power relay with main contacts connected between a source of electrical power and a load are, and auxiliary contacts that close temporarily, before the opening and closing of the main contacts and briefly open after opening and closing the main contacts, and a solid-state arc suppression circuit responsive to the operation of the auxiliary contacts and in parallel connected to the main contacts to create a low impedance current path around the main contacts around for arc suppression, wherein a steering or control relay has contacts that are between the electrical power source and connected to the load for controlling the characteristic or type of current to the load whereby the Current has a first type or characteristic when the control relay is de-energized or switched off and a second characteristic when the control relay is energized or on, and control circuitry associated with the power relay and the control relay is connected to control

809826/0777

its operation, the control circuit device having a circuit connection via the control relay, whereby the control relay can neither be energized nor de-energized while current is flowing through the contacts of the power relay closes.

Further advantages, features and possible applications of the present invention emerge from the following description in conjunction with the drawings. Show it:

1 schematically shows an electrical diagram of a motor direction control circuit,

Fig. 2 is a schematic representation of a circuit used to control the direction of rotation of the motor is used,

3 shows the schematic representation of one of the power relay contactors and the associated arc suppression circuit device,

4 shows the operation of the auxiliary contact, assigned to each of the power relay contactors,

5 is a partial electrical schematic diagram of a heater control circuit and FIG

809826/0777

- u . 2755459

6 shows a detail of the steering or control relay showing the anchoring or clamp bracket to prevent short circuits.

The following is a preferred embodiment of the invention explained in more detail as an example. Figure 1 shows an embodiment of the invention, namely a three-phase motor 10 with three windings 11, 12 and 13, which are at the terminals 16, 17 and 18, which in turn with a AC power source 20 are connected via input terminal connections 21, 22 and 23.

The current for the motor 10 is controlled by means of the power relay 30, which is a plurality of normally open contactors 32, 33 and 34, the single-pole changeover contactor 35 and the coil 36. Contactors 32-34 are preferred provided with arc suppressors 37-39, the details of which are described below.

The direction of rotation of the motor 10 is controlled by a control relay 40. This relay has four double or changeover contactors 42-45 and a spool 46. When terminals 22 and 23 are de-energized, they are above normal closed elements of the contactors 42 and 43 are connected to the terminal 17 and 18, respectively, and thus leave the motor 10 rotate in forward direction; and when relay 40 is energized, the connection between terminals 22 and 23 and the Connections 17 and 18 reversed so that the motor in the

809826/0777

reversed direction turns.

The circuit shown in FIG. 1 is designed in such a way / that the application and removal of current to the motor 10 and from this always takes place via the contacts of the power relay 30; the position of the contacts of the control relay are not changed when power is applied to the motor is applied.

Control circuit devices are provided for controlling the power relay and control relays for controlling the direction of rotation of the motor to change that the control relay contacts are switched from one position to the other while power is applied to the motor is.

The control circuit device has the circuit arrangement shown in Figure 2, which preferably has a stop button 50 with the normally closed Contacts 51; also a (FWD) forward button 52 with the normally open contacts 53 and the normally closed contacts 54; and a (REV) reverse key 55 with normally closed contacts 56 and normally open contacts 57. AC power is supplied to input terminals 60 and 61, and when it is desired to rotate the motor 10 in the forward direction. let, the push buttons 52 are depressed and the output terminal 62 is in electrical

809826/0777

Connection to port 60 via the normally closed Contacts 51 and 56 and the now closed contacts 53 of the forward button 52 brought.

According to Figure 1, the terminal 62 is on the normally closed contacts 45 of the relay 40 and with one side a bridge rectifier 70 connected. The other side of the bridge rectifier is to the common connection terminal 61 connected. The capacitor C1 serves as a hum filter to prevent vibration or rattle of the relay. So when the forward button is pressed, power is applied to the relay solenoid 36 to that relay to excite and electrical:. Make connections between terminals 21-23 and the windings of the motor 10.

A hold circuit is provided across the normally open contacts 35 of relay 30, one of which contacts terminal 72, the other contact being connected to normally closed contacts 44 of relay 40 and is thus connected to the terminal 73, whereby a parallel current path is provided around the contacts 53 (Figure 2) is. Thus, once the forward button is pressed, the relay 30 will remain energized until either the stop button 50 or the reverse key 55 is operated. Depressing the stop button 50 takes the holding current from the relay 30, this will de-energized, and contactors 32-35 open.

809826/0777

If it is desired that the motor rotate in the reverse direction, then the reverse key 55 is depressed. This opens the contacts 56; and thus the performance to coil 36 de-energizing relay 30 (assuming it was energized) removed; and at the same time becomes the contact 57 is closed and thereby connects the terminal 60 to the terminal 71 via the contacts 54 of the Key switch 52.

The terminal 71 is connected to one side of the bridge rectifier 75, the other side of which is connected to the common terminal 61. The output of the rectifier 75 is applied to the coil 46 of the relay 40 and causes it to be energized after a time delay which is determined by the values of the capacitor C2 and the resistor R1, thereby reversing the connection between terminals 22-23 and terminals 17-18. This time lag is sufficient to allow the relay 30 to be de-energized and the arc suppression circuits aside Action occurs before relay 40 is energized, thereby protecting contacts 42-44 of control relay 40. if the relay 40 is energized, current is fed to the bridge rectifier 70 via the normally open contacts 45, so that the relay 30 is energized and power is supplied to the motor 10.

The holding current for the relay 40 is derived from the terminal 72 via the contacts 35 of the relay 30 and the normally

809826/0777

Open contacts 44 of relay 40 to terminal 76, whereby a parallel path for contacts 57 is provided will.

When the stop button 50 is depressed, power is drawn to both relay coils and the relay 36 is de-energized which opens its contactors or contactors 32-35. The relay 40 remains energized for a short time, however, due to the action of the capacitor C12, which therefore acts as a time delay device and ensures that the contactors of the relay 40 open after those of the relay 30. Thus, any arcing that occurs as a result of the Sj. _c h -opening of the circuit to the motor could occur, handled by the contactors 32-34 of the power relay rather than by the contact devices or contactors in the control relay 40, and for this very reason the contactors of the power relay are preferably provided with arc suppressors 36-38.

Thus, if the motor 10 is to be rotated in the reverse direction, the relay 40 is first energized or allowed to attract, and all of its contacts close prior to energizing relay 30.

Figure 9 is a schematic representation of one of the contact devices or contactors 32 of relay 30 and its associated arc suppression circuit 37. For example, contactor 32 is shown, although it will be understood

809826/0777

that the relay 30 has three similar contactors in a stacked position, each with its own arc suppression circuit.

The solenoid 36 of the relay 30 is magnetically coupled to a fitting 80 and pulls it down when that Relay is energized. The fitting rotates about a pivot point 81 and is urged away from the solenoid by a spring 82. An isolated hinge member 83 is pivotable at the end of the upper contact clip 85 attached. The part 83 also extends upwards and occurs with similar straps for the other contactors of the relay engaged.

The contactor 32 has a first main contact element 90, which is carried by the contact bracket 85, and has a second main contact element 92, which is arranged directly opposite this and carried by a contact bracket 95 will. Both contact clips 85 and 95 have sufficient cross-sectional area to carry the motor current on a continuous basis and yet are resilient or flexible enough to flex while the relay is operating.

As shown in Figure 4, the contact clip extends 85 through the joint or the connection 83, and the end of the bracket 85 forms an auxiliary contact 96, which is of a fixed Contact 97 is spaced apart.

809826/0777

The contact clip 85 also goes through an opening 99 in one solid insulated support member 100 therethrough. The part 100 also extends upward and serves in a similar manner with respect to the other contactors of the relay.

The arched part 101 of the opening 99 is arranged with respect to the contact clip 85 that it engages with the clip occurs as soon as the solenoid 36 pulls the fitting and thus the part 83 downwards when the relay is energized. As a result, contacts 96 and 97 close instantly prior to closing contacts 90 and 92 as shown by dashed line 85a; therefore the contacts occur 90 and 92 engage and close the main circuit; and finally contacts 96 and 97 open as shown by dashed lines 85b. On the other hand, when the relay is de-energized, contacts 96 and 97 act in a similar manner Manner engaged as soon as the fitting 80 begins to move upwards; contacts 90 and 92 then open; and then open the contacts 96 and 97. We return again to the figure, according to which the main connections of the triac 110 in parallel to contactor 32, the control electrode of the triac being connected to contact 97. While the The relay is thus control current immediately before the closing and during the closing of the main contact elements 90 and 92 of the contactor 32 led to the triac 110, and then the Control current removed, which gives the possibility that the full current is passed through the main contacts and a surface seizure or etching effect is caused, the

809826/0777

may be necessary on the surface of the main contacts so that they can then carry the full load. By removing the control current after closing the main contacts, the triac stops carrying current at the first zero crossing of the current, and the main contacts should Having developed a high resistance, the triac will not be forced to conduct current for a significant amount of time.

After de-energizing or switching off the relay, the control current to the triac is provided via contacts 96 and 97 as soon as the relay fitting 80 begins to move upwards, contacts 90 and 92 then open while the triac is fully operational; and after the contacts have fully opened, contacts 96 and 97 then open and take control current from the triac.

Those skilled in the art will recognize that other arc suppressors may be used in conjunction with the shooters 32-34 of the Relays 30 could be used or that these contactors could be constructed to form any arcing handle which occurs when power is switched to motor 10. The control relay 40 can on the other hand, have a simpler and cheaper structure, and the total cost of a contactor that constructed according to the invention can be lower and the performance can be higher than that of the known devices. The contactor described above is also smaller than the known devices. For example, takes a

809826/0777

Protects this design, NEMA, size 2, about 226 cm (35 square inches) less surface area than a similarly calculated contactor based on conventional Standards is established.

Figure 5 illustrates another embodiment of the Invention in which a load, in this case an electrical heater / which is designated 110, is connected to the source of electrical current 115 by means of contacts 132 and 133 of a power relay 130. Contacts 132 and 133 are provided with arc suppressors 37 and 38, respectively, which are shown in FIG work in the manner previously described. The current source 115 is shown as a Y-connected transformer secondary part with output terminals 120-123, the Output terminal 122 is a common terminal (midpoint). For example, the voltage between terminals 122 and one of terminals 120, 121 and 123 are approximately 277 volts, while the voltage between terminals 120-121, 121-123 and 123-120 is approximately May be 480 volts, although it will be understood that other voltage levels can be used.

The control relay 140 controls the nature or type of current applied to the load 110. In the de-excited state of relay 140 is a voltage having a first property, namely 277 volts, from terminal 122 across the normally closed contacts 143 with the load

809826/0777

tied, and when relay 140 is energized, a Voltage of a second property, namely 480 volts, above the normally open contacts created. Therefore, the magnitude of the current flowing through the heater 110 depends on the control relay.

The control relay 140 also has auxiliary contacts 44 and 45, and the power relay 130 has auxiliary contacts 35, the operate in the same way as the auxiliary contacts of the same reference number as shown in connection with Figure 1 and is described.

In operation, relay 140 is controlled in the same manner as relay 40 of FIG. H. the relay is neither energized nor de-energized while current is flowing to the load. the Circuitry shown in Figure 1 can be used to ensure that the contacts of relay 130 comprising arc suppressors 37 and 38 bear the brunt of controlling the flow of current to the load and that the contacts of relay 140 never open or close while current is flowing through them.

Figure 6 is an enlarged view of the control relay 140 showing the details of its structure. The relay has a solenoid 146, which magnetically with a bracket 150 is coupled to pull the bracket down when the relay is energized. The fitting is from the solenoid is biased away by a spring 151. One

809826/0777

isolated connection 152 connects the fitting to the exterior End of a movable contact clip 155, which with a upper contact part 156 and a lower contact part 157 is provided. The contact clip 155 is flexible and is on his the other end is supported between insulated spacer blocks 160 which are supported on the arm 162.

The relay also has an upper flexible contact clip 165 which has a contact part 166 which is in the normally closed position (as shown) makes contact with contact portion 156 to provide a current path to be provided between the connections 122 and 124. The relay also has a lower flexible contact clip 167, the at its end has a contact part 168 which is gripped by contact 157 when the relay is energized or with this engages to provide a current path between terminals 123 and 124. Both contact clips 165 and 167 are supported within isolated spacers 160 as shown.

The contacts 156 and 166 or 157 and 158 can be welded together sufficiently that they no longer separate, after the relay has either been energized or de-energized. Should this happen and should be the center contact bracket move enough to allow contact with the other contact, then a short circuit between the terminals would occur 122 and 123 exist. Referring briefly to Figure 5, it will be noted that these connections are one turn of the current

809826/0777

source 115 are connected and that this situation therefore causes considerable damage to both the control relay and could also cause the power source.

According to the invention, a spreader bar 170 is therefore provided, which is formed from a rather inflexible heavy steel piece and extends out of the space between the insulated spacers 160 and then downwards, whereby the end is bent upward and is located near the contact 166. In the de-energized state of the relay, the contact part 156 engages with the contact 166 and leaves the Contact clip 165 are bent a little upwards, and therefore the end of the expansion clip 170 is at a distance of the lower surface of the contact clip 165 is arranged. However, when the relay is energized, the contact clip 155 moves down, but the contact clip 165 will prevented from moving downward by the end of the expansion bracket 170.

Similarly, a lower spreading bracket 175 is assigned to the lower contact bracket 167, and its end is next to the Contact part 168 arranged. When the relay is energized, the contact 157 engages the contact portion 168 and causes the flexible contact clip 167 to move down and move something away from the end of the spreader bar 175. If that However, relay is de-energized, the spreading bracket 175 prevents the contact 168 from moving upwards, and should one The weld between the contacts must be strong enough to prevent

809826/0777

he also changes that .the contact clip 155 is sufficient moved up to create a current path between contact portions 156 and 166.

A similar arrangement could be used with contacts 42 and with the control relay 40 shown in FIG. 1 to prevent inadvertent shorting between terminals 22 and 23.

809826/0777

-Or

Blank page

Claims (14)

Dr. Hans-Heinrich Willrath t Dr. Dieter Weber Dipl.- Phys. Klaus Seiffe * PATENT LAWYERS D-62 WIESBADEN ι S / B P.O. Box MM 6145 Gustav-Freyug-Strat «IS S? (061 (1) J7 «7tt Tdegnmmadreuei WILLPATENT Telex: 4 - 186 247 File 6496 Power Management Corporation 65 West Park Road, Centerville, Ohio 45459 / USA Priority; December 22, 1976 in USA, serial no. 753 516 and September 14, 1977 in USA, Serial-No. 833 234 Claims ( 1./ control circuit for the use of power at an electrical load with a power relay with main contacts that are connected between the source of an electrical current and a load, and with auxiliary contacts that are temporarily open and shortly before Posts * «* Frankfurt / Main '' AC. Wiesbaden. Account number (76807 2753459 Close the main contacts close and open shortly thereafter, and with a solid-state arc suppression circuit, which responds to the activity of the auxiliary contacts and is parallel to the main contacts Creation of a low impedance current path around the main contacts to suppress arcing, thereby characterized in that a control relay (40) has contacts (42-45) between the electrical Current source (20) and the load (10) are connected to control the property of the current towards the load (10), whereby the current has a first characteristic when the control relay (40) is de-energized and a second characteristic has when the control relay (40) is energized, and that a control switching device (50-57; Figure 2) with the power relay (30) and the control relay (40) is connected to control the operation of the same and that the control switching device has a circuit connection via the control relay (40), whereby the latter neither energized can still be de-energized while current flows through the contacts (32-35) of the power relay (30). 2. Device according to claim 1, characterized in that the load is an electric motor (10) and that the control relay (40) controls the direction of the current flow through the motor (10) in such a way that when the control relay (40) is de-energized the motor (10) rotates in one direction and when the control relay (40) is excited, the motor (10) rotates in the opposite direction Direction turns. 809826/0777 3. Device according to claim 1, characterized in that the load is an electrical heating device (110) and that the control relay (140) controls the voltage which is applied to the heating device (110), and that when the control relay (140) is energized, the voltage to the heating device (110) has a first value and when de-energized of the control relay (140), the voltage applied to the heating device (110) has a second magnitude. 4. Device according to one of claims 1-3, characterized in that that the power relay (3O) has contacts (32-35) between the electrical power source (20) and the load (10) are connected for controlling the application of power to the load (10) that the Control relay (40) has contacts (42-45) which between the power source (20) and the input terminals (16-18) the load (10) are connected for controlling the property of the current flow through the load (10), wherein the current has a first property when the control relay (40) is de-energized and has a second property, when the control relay (40) is energized, and that the control circuit (50-57) with the power relay (30) and the Control relay (40) is connected for controlling the operation thereof and that the control circuit has a first circuit connection has by the control relay (40), whereby when current of the second property is desired is, the contacts (32-35) close the power relay (30) after the control relay (40) is energized, and that the 8Π9Β26 / 0777 Control circuit also includes a time delay device (C2, R1) has to delay the de-energization of the control relay (40). until after the contacts (32-35) of the power relay (30) have opened and the current flowing to the load has been completely removed. 5. Device according to one of claims 1-4, characterized in that that each contactor (32-35) or each of the contact devices (33-35) of the power relay (30) arc suppression devices (37-39) are assigned. 6. Device according to one of claims 1-5, characterized in that the arc suppression device (37-39) have auxiliary contacts (96) on the power relay (30), semiconductor devices (110) whose power-carrying connections are connected via the contactor (32) are and with a gate terminal which is connected to a gate excitation signal via the auxiliary contacts (37) and has an actuating device for closing the auxiliary contacts immediately before either closing or opening the contact and before opening the auxiliary contact immediately after either closing or opening open wherein the potential is momentarily reduced by the contact of the contact is not maintained for the prevention of arcing during opening or closing, and wherein the gate energizing signal when the switch _Sc Hütz is closed, whereby the semiconductor device (110) is protected against overload in the event of that the switching 809826/0777 2756A59 contactor should or should not close. 7. Device according to claim 4, characterized in that a tent delay device of the control device for whose de-energization delay is assigned a length of time, which is longer than the tent that is used for de-excitation of the power relay (30) is required. 8. Device according to one of claims 1-7, in particular for applying power to a three-phase electric motor and for controlling its direction of rotation, characterized by first, second and third power relay contactor devices, connected between a source of electrical power and the motor, arc suppressors that are transverse Connected via each power relay contactor are first, second and third motor power input connections, devices for connecting the first power relay contactor devices to the first power input connection, control relay contactor devices which connect the second and third power relay contactor devices to the second and third power input connection in a first combination , if they are not operated, such that the motor rotates in a forward direction, and for the connection of the second and third power relay contactor devices with the second and third power input terminals in a second Combination, when actuated, such that the motor 809826/0777 rotates in the reverse direction, a power relay actuator device for the actuation of the first, second and third power relay contactor devices in such a way that that power is applied to the first power input connection and to the control relay contactor device, Control relay actuator devices for actuating the control relay contactor devices, devices for energizing the power relay actuators directly such that the first, second and third power relay contactors are operated for the forward rotation of the motor and by means of excitation of the Control relay actuators and the power relay actuators, such that the first, second and third power relay contactor devices are actuated, after the control relay contactor is actuated, and means for causing the control relay protection device remains actuated until after the first, second and third are disconnected or disengaged Relay contactor devices, whereby the actuation and its opposite of the control relay contactor device does not occurs while power is on, preventing arcing across the control relay contactor will. 9. Device according to one of claims 1 to 8, characterized in that that the relay has a solenoid, one magnetically coupled to it for actuation thereby Has fitting, a movable contact bracket 809 8 26/0777 which is connected to the fitting by an insulated connection, the contact bracket in the vicinity has a contact at its end, and has a flexible contact bracket spaced from the movable Contact clip is arranged, and has a contact for engagement with the contact on the movable Contact bracket when the fitting is in a first position, and that a spreading bracket (170, 175) made of quite inflexible Material extends next to the flexible contact clip (165) and has an end which next to the Contact (156, 166) is arranged and prevents the flexible contact clip (165) from the movable contact clip (155) follows when the fitting (150) moves into a second position in the event that the contacts with each other be welded. 10. Device according to one of claims 1-9, characterized in that that the relay has a second flexible contact bracket (167) which is movable at a distance from the first Contact clip (165) is arranged and has a contact for the soaking grip with the contact the movable contact bracket when the fitting is in the second position, and a second expansion bracket (175) is assigned to the second flexible part to prevent it from the movable contact clip follows when the fitting moves from its second position to its first position, which prevents that a current path is created between the flexible contact 80982S / 0777 -β- 2755459 bracket and the second flexible contact bracket, if the contacts are welded. B09826 / 0777