WO2005036579A1

WO2005036579A1 - Device having relay

Info

Publication number: WO2005036579A1
Application number: PCT/JP2004/014728
Authority: WO
Inventors: Shinya Yamada; Mikio Sahashi; Masahiko Niino; Katsumi Furuyama; Katsuyuki Fukao; Akihiko Matsuya; Makoto Yamaguchi; Kazuo Itoh
Original assignee: Yamada Electric Mfg. Co., Ltd.
Priority date: 2003-10-08
Filing date: 2004-10-06
Publication date: 2005-04-21

Abstract

A device having a relay exhibiting a reduced ratio of the operation current during an overload and that during a lock. A heater (33) is provided such that a thermo-switch part (40) is in a contact position during ordinary temperatures and in a noncontact position during high temperatures. If an excessive current flows without rotation of a motor (M) at a startup, a current flows into the heater (33) side, so that a heating of the heater (33) causes a main bimetal (21) to immediately interrupt the current. After a start of the motor (M), a conveyance of heat from a compressor turns on the thermo-switch part (40), thereby short-circuiting the heater (33) side. In this way, even if an excessive current instantaneously flows during driving of the motor, the main bimetal (21) is inhibited from being placed in the noncontact position.

Description

Specification

Equipment with relay

Technical field

The present invention relates to a device including a relay suitable for protecting a compressor constituting a refrigeration cycle, such as an air conditioner and an electric refrigerator.

Background art

[0002] Compressor motors used in air conditioners, etc. are designed to prevent leakage of refrigerant, short-circuit or disconnection of the operating capacitor, and restart in the event of an instantaneous power failure. Under severe conditions, a device that can respond quickly is required. In such a case, the compressor of the air conditioner heats up, but the current of the motor often does not increase so much. Therefore, it was impossible to protect the conventional protector which mainly responds only to the current.

[0003] Therefore, thermal protectors of Patent Documents 1 and 2 have been proposed in which a main protector P having a plate-shaped main bimetal B and the like, which can be installed in a compressor, and a temperature switch TH are integrally provided. This will be described below.

[0004] Fig. 10 shows a circuit diagram of Patent Document 1. A thermoswitch TH1 that closes when the temperature rises to a predetermined temperature with a normally open circuit, and a resistor R1 that is energized by this switch are installed near the main bimetal B of the main protector P, and a series circuit of the thermoswitch TH1 and the resistor R1 is loaded. Is connected in parallel with the motor M.

[0005] That is, the motor M is connected in series to the power supply E via the terminals a and b at both ends of the main bimetal B of the main protector P, and one end of the resistor R1 is connected to the output terminal b of the main bimetal B. The other end is connected to thermoswitch TH1 via lead c, and the other end of this thermoswitch is connected to other phases of the power supply by lead d!

[0006] With this, when the motor M is overloaded or the rotor is restrained, the main bimetal B inverts due to the temperature rise of the main bimetal B due to the overcurrent, as in a normal protector. When the current is normal and only the temperature rises, the thermoswitch TH1 is closed, the current is passed to the resistor R1 to generate heat, and the circuit is shut off by inverting the main bimetal B.

Next, FIG. 11 shows a circuit diagram of Patent Document 2. Normally closed thermoswitch TH2 and main switch Protector P is connected in series with motor M, which is the load. The main protector P is provided with a heater wire R2 near the main bimetal B, and always heats this bimetal B. If only the temperature rises, the thermoswitch TH2 opens to prevent the motor M from burning. Wear.

Patent Document 1: Japanese Utility Model Laid-Open No. 79240

Patent Document 2: Japanese Patent Application Laid-Open No. 7-262895

Disclosure of the invention

Problems to be solved by the invention

[0008] However, in the thermal protectors of Patent Documents 1 and 2, while emphasizing protection characteristics when the motor is in a locked state (locked state) at the time of starting, the overload operating current is reduced. There is a problem that the main bimetal operates even in the expected normal operation. In other words, if it takes time before the main bimetal is disconnected while the motor is in the constrained state at the time of low-temperature start, excessive current flows through the motor with low resistance in the low-temperature state, which may cause burnout. Therefore, the operating current of the main bimetal had to be set lower. For this reason, the operating current (overload operating current) of the main bimetal when overcurrent flows during operation was reduced, which sometimes hindered normal operation. For example, when starting the operation of a refrigerator where the inside of the refrigerator is at room temperature, a current exceeding the overload operating current flows until the temperature in the refrigerator decreases, and the main bimetal operates, and the motor There was a case where the malfunction of turning on and off repeatedly occurred.

[0009] An object of the present invention is to provide a device provided with a relay in which the ratio of the operating currents at the time of overload and at the time of locking is reduced.

Means for solving the problem

[0010] In order to achieve the above object, the invention of claim 1 relates to an apparatus provided with a relay made of a main bimetallic cable that interrupts a current by increasing an energized current,

A positive temperature coefficient thermistor element connected in parallel to said main bimetal and heating said main bimetal;

A heater connected in series to the main bimetal and heating the main bimetal; and a thermometer connected in parallel to the heater and connecting a contact as the temperature increases. It is a technical feature to include a switch portion.

[0011] The invention according to claim 2 is an apparatus provided with a main bimetallic relay for interrupting a current by increasing an energized current.

A heater connected in series to the main bimetal to heat the main bimetal; and a thermoswitch unit connected in parallel to the heater to disconnect the contact at low temperature, connect the contact at medium temperature, and disconnect the contact at high temperature. This is a technical feature.

[0012] The invention according to claim 3 is an apparatus provided with a relay composed of a main bimetallic force that interrupts a current by increasing an energized current.

Technical features include a heater connected in series to the main bimetal for heating the main bimetal, and a negative temperature coefficient thermistor element connected in parallel to the heater.

[0013] The invention according to claim 4 is an apparatus provided with a relay composed of a main bimetallic force that interrupts a current by increasing an energized current.

A heater connected in series to the main bimetal for heating the main bimetal; and a heater connected to a side where power is supplied to the main bimetal without passing through the heater due to an increase in temperature, and the temperature is reduced. And a thermo-switch unit connected to the side to be energized through the heater.

The invention's effect

[0014] In the equipment provided with the relay according to claims 1 and 4, a heater for heating the main bimetal is connected in series with the main bimetal, and the heater is connected at room temperature by a thermoswitch unit and cut off at high temperature. Therefore, if an overcurrent flows without the motor rotating (locked state) at startup at normal temperature, current flows to the heater side, and the main bimetal is immediately Cut off the current (shortening the SZT (relay operation time during lock) and suppressing the temperature rise of the motor winding at this time). After the motor starts, the temperature becomes high, the thermoswitch turns on, and the heater is short-circuited. Therefore, even if an overcurrent flows momentarily during the operation of the motor,

Since the main bimetal is not interrupted, stable operation can be performed (UTC (overload operating current) can be increased). Here, when the main bimetal is disconnected, a current flows to the side of the PTC thermistor element connected in parallel, so that the main bimetal is heated by the PTC thermistor element and the recovery time is delayed. Therefore, even if the main bimetal is repeatedly turned on and off while the motor is kept in a constrained state, the current does not continue to flow through the winding for a long time, so that the motor is not damaged. Furthermore, when the temperature is low, a current is supplied to the heater side by the thermoswitch section to shorten the operation time of the main bimetal, so that the temperature rise of the motor, which initially rises sharply, can be suppressed. Here, even if the calorific value at low temperature is large and the temperature is close to the rating even when the voltage is reduced, and a positive temperature coefficient thermistor element that can secure the calorific value is used, even if the voltage drop occurs at low temperature, It is possible to reliably protect the motor.

[0015] In the apparatus provided with the relay according to claim 2, a heater for heating the main bimetal is connected in series with the main bimetal, and the heater is connected at a low temperature by a thermoswitch unit and cut off at a medium temperature. If the motor does not rotate (locked state) and an overcurrent flows during startup at low temperatures, current flows to the heater side, and the main bimetal immediately shuts off the current due to the heating of the heater. After the motor starts, the temperature becomes medium (operating temperature), the thermoswitch turns on, and the heater is short-circuited. For this reason, even if an overcurrent flows instantaneously during motor operation, the main bimetal is not disconnected and stable operation can be performed. On the other hand, when the compressor power becomes high without leakage of the refrigerant and the amount of current is increased, the main bimetal can immediately cut off the current by heating the heater by connecting the heater with the thermoswitch portion. Here, the positive temperature coefficient thermistor element connected in parallel with the main bimetal does not damage the motor even if the constrained state continues.

[0016] In the device provided with the relay according to claim 3, a heater for heating the main bimetal is connected in series to the main bimetal, and a negative temperature coefficient thermistor element is connected in parallel to the heater, so that the starting at normal temperature is performed. When the motor does not rotate (locked state) and an overcurrent flows, the current flows mainly to the heater side due to the high resistance of the negative characteristic thermistor element, , The main bimetal immediately shuts off the current. After the motor is started, the temperature becomes high, the resistance of the negative temperature coefficient thermistor element decreases, and the amount of current to the heater decreases. For this reason, even if an overcurrent flows instantaneously, the main bimetal is not disconnected, and stable operation can be performed. Here, the positive temperature coefficient thermistor element connected in parallel to the main bimetal does not damage the motor even if the locked state continues.

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment]

A first embodiment in which a device equipped with a relay of the present invention is applied to a thermal relay will be described with reference to FIGS. FIG. 1 is a front view of the thermal relay cut along a center line.

The thermal relay 10 is attached to an outer surface of a protected body such as a compressor. The outer shell 12 made of an insulating material also has a cylindrical case 13 whose lower end is open and a cover force for closing the open end. The cover comprises a thermo base 14 of a thermo switch section 40 and a cap 16. Inside the cylindrical case 13, a protector section 20, a normally open thermoswitch section 40 that closes at a predetermined temperature, and a flexible insulating material 15 are housed.

[0018] A mechanical configuration of the protector unit 20 will be described. The protector section 20 includes a dish-shaped main bimetal 21, an adjustment screw 22, and a coil spring 25. The main bimetal 21 is pressed against and held by a head 23 of the adjustment screw 22. The adjusting screw 22 is composed of a screw portion 22A and a head 23, and is fixed with a heat-soluble metal 24. The main bimetal 21 is connected to the tab terminal 30 via a fixed contact described later. Above the main bimetal 21, a heater 33, such as a chrome wire, for heating the main bimetal 21 from above is arranged, and below the main bimetal 21, an annular positive electrode that also heats the main bimetal 21 downward. The characteristic thermistor element 50 is provided.

Next, a mechanical configuration of the thermoswitch section 40 will be described. The thermo switch section 40 includes a thermo movable contact 45 attached to a movable contact plate 44, a movable terminal 43 supporting the movable contact plate 44, a fixed contact 42 in contact with the thermo movable contact 45, and a movable contact plate. It consists of a dish-shaped thermo-bimetal 46 that swings 44. The thermo-bimetal 46 transfers the heat of the protected body such as a compressor through the cap 16, and keeps the thermo movable contact 45 and the fixed contact 42 disconnected at a low temperature of 40 ° C. Turns over when C exceeds The moving contact 45 and the fixed contact 42 are brought into contact. Thermobimetal 46 reverses again when the temperature drops below 30 ° C. The fixed contact 42 is connected to the tab terminal 47 as described later.

FIG. 2 is a circuit diagram of the thermal relay 10. The thermal relay 10 is arranged between the AC power supply E and the motor M of the compressor. In the thermal relay 10, a positive characteristic thermistor element 50 is connected in parallel with the main bimetal 21, a heater 33 is connected in series with the main bimetal 21, and a thermoswitch section 40 is connected in parallel with the heater. That is, the above-described tab terminal 30 is connected to the movable contact 3 la of the main bimetal 21 via the fixed contact 29 a on the main bimetal 21 side. The movable contact 31b of the main bimetal 21 is connected to the heater 33 via a fixed contact 29b. The heater 33 is connected to the tab terminal 47 side!

When an overcurrent flows into such a protector section 20 and the main bimetal 21 operates to cut off the contacts 29a, 29b, 31a and 31b, and the temperature drops, the main bimetal 21 returns and the contacts 29a and 29b, 31a, 3 lbs reclose. If this is repeated many times, the contacts will be welded and the main bimetal 21 will be inoperable and dangerous.However, both the heat generated by the main bimetal 21 and the temperature rise of the compressor to be protected will cause the head of the adjusting screw 22 The heat fusible metal 24 joining the part 23 and the screw part 22 is melted, the main bimetal 21 is pushed up by the coil spring 25, and the contacts 29a, 29b, 31a, 31b are cut off. Thereafter, the main bimetal 21 does not return to the old position, and becomes a non-return type operation.

The operation of the above-described thermal relay will be described with reference to FIG.

A heater 33 for heating the main bimetal 21 is connected in series with the main bimetal 21, and the heater 33 is connected at normal temperature by a thermoswitch unit 40 and is turned off at high temperature, so that the motor M is started at the time of normal temperature. If an overcurrent flows without rotating (locked state), current flows to the heater 33 side, and due to the caloric heat of the heater 33, the plate-shaped main bimetal 21 immediately reaches the operating temperature of 160 ° C and is inverted and fixed. The contacts 29a and 29b are separated from the movable contacts 3 la and 3 lb to cut off the current. That is, SZT (relay operation time at the time of locking) can be shortened, and the temperature rise of the motor winding at this time can be suppressed.

On the other hand, after the motor M is started, heat is transmitted from the compressor, and when the thermoswitch section 40 reaches 40 ° C., the thermoswitch section 40 is turned on and the heater 33 is short-circuited. For this reason, during the operation of the motor, Even if an overcurrent flows, the main bimetal 21 is not disconnected, so that stable operation can be performed. That is, UTC (overload operating current) can be increased, and the ratio of the current value of SZT (relay operation time during lock) to UTC can be reduced.

The UTC characteristics will be described in more detail with reference to the graph of FIG. In the figure, the vertical axis indicates the operating current of the main bimetal 21, the horizontal axis indicates the operating temperature, the broken line indicates the case with a heater, and the dashed line indicates the case without a heater. In the first embodiment, at 40 ° C. or lower, UTC characteristics when there is a heater are taken, and when it exceeds 40 ° C., UTC characteristics when there is no heater are taken. Thus, the operating current value of the main bimetal 21 during operation (high temperature) is increased while the operating current value of the main bimetal 21 during startup (low temperature) is reduced.

On the other hand, in the thermal relay 10 of the first embodiment, when the main bimetal 21 is cut off, a current flows to the side of the PTC thermistor element 50 connected in parallel. 21 is heated and the recovery time is delayed. Therefore, even if the main bimetal 21 is repeatedly turned on and off after the motor M is kept in the constrained state, the current does not continue to flow through the motor winding for a long time, so that the motor M is not damaged.

The operating temperature at the time of SZT (when the motor is in a restrained state at the time of starting the motor) will be described with reference to the graph of FIG.

In the figure, the vertical axis represents the temperature of the motor, and the horizontal axis represents time, and the solid line represents a conventional relay, such as Patent Document 1. The broken line indicates the case where the heater 33 is turned on and off by the thermoswitch unit 40. When the heater 33 is turned on and off by the thermo-switch section 40, the temperature of the compressor rises after the motor temperature rises, and the thermo-switch section 40 comes into force contact with a further delay. Therefore, by flowing a current to the heater 33 side by the thermoswitch section 40 and shortening the operation time of the main bimetal 21, the initial operation time becomes longer in a low temperature state, and the phenomenon that the temperature of the winding rapidly rises is reduced. Can be suppressed.

Further, the dashed line indicates the case where the heater 33 is turned on and off by the thermoswitch section 40 and the main bimetal 21 is heated by the positive characteristic thermistor element 50. The main bimetal 21 is heated by the positive temperature coefficient thermistor element 50, and the recovery time is delayed. That is, the off time becomes longer than the on time. Therefore, even if the main bimetal 21 repeatedly turns on and off after the restraining state of the motor M continues, current does not continue to flow through the motor winding for a long time. The temperature rise of the motor can be suppressed.

Furthermore, in the first embodiment, the use of the positive temperature coefficient thermistor element 50 that generates a large amount of heat at a low temperature and can secure a heat generation close to the rated value even when the voltage is reduced enables the voltage drop at a low temperature. Even if the occurrence of occurs, it is possible to reliably protect the motor.

[Second Embodiment]

A relay according to a second embodiment of the present invention will be described with reference to FIG. The electric circuit of the relay of the second embodiment is the same as that of the first embodiment described above with reference to FIG. However, in the first embodiment, the thermoswitch section 40 includes only one thermo-bimetal (bimetal for improving characteristics) 46, but in the second embodiment, the thermoswitch section 40 includes only one bimetal (for improving characteristics) 46. In addition, gas leak detection metal 52 is placed back to back. The thermo-bimetal (bimetal for property improvement) 46 reverses at 40 ° C / 30 ° C as in the first embodiment, and the bimetal 52 for gas leak detection is designed to detect high temperatures when gas leaks from the compressor. It is set to reverse at 120 ° C / 60 ° C.

FIG. 5 (A) shows a low temperature (initial) state! Here, the thermometal (metal for improving characteristics) 46 is convex downward, and the bimetal 52 for gas leak detection is convex upward, and the movable contact 45 and the fixed contact 42 of the thermoswitch 40 are disconnected. Electricity to heater 33 is being supplied. When the motor is locked at start-up, the main bimetal 21 can be operated immediately as described above with reference to FIG.

FIG. 5B shows a medium temperature (operating) state. Here, the gas leak detection bimetal 52 continues to protrude upward, but the thermometal (metal for property improvement) 46 protrudes upward (reversed), and the movable contact 45 Is in contact with the fixed contact 42, and the heater 33 is short-circuited. As described above with reference to FIG. 2, the main bimetal 21 can be prevented from operating even when the overload current flows instantaneously.

FIG. 5 (C) shows a high temperature (gas leak) state! Here, the temperature of the thermo bimetal (bimetal for property improvement) 46 is upwardly convex (reversed), and the temperature rises to 120 ° C or more due to gas leakage, so that the bimetal 52 for gas leakage detection becomes convex downward. (Reversed), the thermoswitch section 40 is turned off, the power is supplied to the heater 33, and the main bimetal 21 is operated immediately. In the second embodiment, only the temperature is increased without increasing the current due to refrigerant leakage or the like. Even when the motor rises, the motor can be quickly protected.

[0033] [Third embodiment]

The circuit configuration of the relay according to the third embodiment will be described with reference to FIG. In the first embodiment described above with reference to FIG. 2, the thermoswitch unit 40 is connected in parallel with the heater 33. On the other hand, in the third embodiment, a negative characteristic thermistor element 54 is connected in parallel with the heater 33.

In the relay according to the third embodiment, a heater 33 for heating the main bimetal 21 is connected in series to the main bimetal 21, and a negative characteristic thermistor element 54 is connected in parallel to the heater 33, so that the normal bimetal 21 is connected. If the motor M does not rotate at startup and an overcurrent flows (locked state), the current flows mainly to the heater 33 because the negative-characteristic thermistor element 54 has a high resistance. Bimetal 21 shuts off current immediately. After the motor is started, the temperature becomes high and the resistance of the negative characteristic thermistor element 54 decreases, and the amount of current to the heater 33 decreases. For this reason, even if an overcurrent flows instantaneously, the main bimetal 21 is not disconnected and stable operation can be performed.

The UTC characteristics of the relay according to the third embodiment will be described with reference to the graph of FIG. In the figure, the vertical axis shows the operating current of the main bimetal 21, and the horizontal axis shows the operating temperature. In the third embodiment, an intermediate UTC characteristic between a case with a heater and a case without a heater is taken. As a result, the operating current value of the main bimetal 21 during operation (high temperature) is increased while the operating current value of the main bimetal 21 during startup (low temperature) is reduced. In the third embodiment, since the negative-characteristic thermistor element 54 is used instead of the thermoswitch section 40 using contacts, there is a high reliability IJ point.

[Fourth Embodiment]

The circuit configuration of the relay according to the fourth embodiment will be described with reference to FIG. In the first embodiment described above with reference to FIG. 2, the thermoswitch unit 40 is connected in parallel with the heater 33. On the other hand, in the fourth embodiment, the thermoswitch section 56 is connected to the side where the power is supplied to the main bimetal 21 without passing through the heater 33 due to the increase in the temperature, and the heater 33 is connected to the side where the temperature decreases. It is configured to be connected to the side to be energized through. This operation is the same as in the first embodiment described above with reference to FIG. To do. In the fourth embodiment, there is an advantage that a part of the current of the heater 33- ^ can be prevented from being diverted due to the contact state of the contacts in the thermoswitch section 40.

[Fifth Embodiment]

The circuit configuration of the relay according to the fifth embodiment will be described with reference to FIG. In the first embodiment described above with reference to FIG. 2, the thermoswitch unit 40 is connected in parallel with the heater 33. On the other hand, in the fifth embodiment, the heater and the thermoswitch section are omitted. Even when only the positive temperature coefficient thermistor element 50 is used as in the fifth embodiment, as the return time of the main bimetal 21 increases, the duty ratio to the motor decreases, and as shown by the broken line in FIG. The temperature rise of the wire can be suppressed.

In the above-described embodiment, even when only the thermoswitch section 40 is used without using the positive temperature coefficient thermistor element as an example in which the positive temperature coefficient thermistor element and the thermoswitch section 40 are used in combination, FIG. As shown by the broken line in (A), the peak value of the temperature rise of the winding at the start in the motor locked state can be suppressed.

Brief Description of Drawings

FIG. 1 is a front view of a relay according to a first embodiment of the present invention, cut off at a center line.

FIG. 2 is an electric circuit diagram of the relay according to the first embodiment.

FIG. 3 is a graph showing UTC characteristics of the relay according to the first embodiment.

FIG. 4 (A) is a graph showing SZT characteristics of the relay of the first embodiment. (B) is a graph showing SZT characteristics of the relay of the fifth embodiment.

FIG. 5 is an explanatory diagram illustrating an operation of a thermoswitch unit according to a second embodiment.

FIG. 6 is an electric circuit diagram of a relay according to a third embodiment.

FIG. 7 is a graph showing UTC characteristics of the relay according to the third embodiment.

FIG. 8 is an electric circuit diagram of a relay according to a fourth embodiment.

FIG. 9 is an electric circuit diagram of a relay according to a fifth embodiment.

FIG. 10 is an electric circuit diagram of the relay of Patent Document 1.

FIG. 11 is an electric circuit diagram of a relay of Patent Document 2.

Explanation of symbols

[0040] 10 relays Outer rim

Cylindrical case

Thermo base

Insulating material

Cap

Protector section

Dish-shaped main bimetal adjustment screw

A thread

Head

Heat-soluble metal

Koinole Spring

Tab terminal

a, 29b Fixed contact a, 31b Movable contact

Heater

Thermoswitch fixed terminal

Fixed contact

Movable terminal

Movable contact plate

Thermo movable contact Thermo bi-metal tab tab terminal

Positive characteristic thermistor element Bimetal for gas leak detection Negative characteristic thermistor element Thermo switch

Claims

The scope of the claims

[1] In a device equipped with a main bimetallic relay that cuts off the current by increasing the current flow,

A relay connected in series with the main bimetal and heating the main bimetal; and a thermoswitch connected in parallel to the heater and connecting a contact when the temperature increases. Equipment.

[2] In a device equipped with a main bimetallic relay that cuts off the current by increasing the current flowing through it,

A heater connected in series with the main bimetal and heating the main bimetal; and a thermoswitch unit connected in parallel with the heater and configured to cut off a contact at a low temperature, connect a contact at a medium temperature, and cut a contact at a high temperature. A device provided with a relay, comprising:

[3] In a device equipped with a main bimetallic relay that cuts off the current by increasing the current flow,

A device comprising a relay, comprising: a heater connected in series to the main bimetal for heating the main bimetal; and a negative characteristic thermistor element connected in parallel to the heater.

[4] In a device equipped with a main bimetallic relay that interrupts the current by increasing the current flowing through it,

A heater connected in series to the main bimetal for heating the main bimetal; and energizing the main bimetal without passing through the heater due to an increase in temperature. And a thermoswitch unit connected to a side to be energized through the heater when the temperature is lowered.

In equipment equipped with a relay consisting of a main bimetallic cable that cuts off the current by increasing the current flow,

A device provided with a relay, comprising: a positive temperature coefficient thermistor element connected in parallel to said main bimetal for heating said main bimetal.