JPS6245783B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overheat protection device for a rotor winding of a rotating electrical machine, which includes a speed detector that rotates integrally with the rotor of the rotating electrical machine.

FIG. 1 shows the circuit configuration of a conventional device of this type. In the figure, 1 is a DC motor excited by a permanent magnet 2, 3 is an armature around which an armature winding 4 is wound, 5 is a brush, 6 is a rotating shaft, 7 is a speed detector that is driven by the DC motor 1 and detects the speed of the DC motor 1, 8 to 12 are parts forming the speed detector 7, 8 is a permanent magnet, and 9 is an armature winding. 10 is the armature wound around, 11 is the brush, and 12 is the DC motor 1.
A rotating shaft 13 is connected to the rotating shaft 6 of the DC motor 1, and an overheat detector 13 is attached to a fixed part of the DC motor 1 in the vicinity of the armature 9, and detects overheating of the armature winding 4.
14 is a signal comparator that compares the speed command signal a and the speed signal b of the speed detector 7; 15 is a signal comparator 1;
A control signal amplifier (hereinafter referred to as an amplifier) 16 amplifies the speed control signal c output from 5, and 16 is a control signal amplifier (hereinafter referred to as an amplifier) which amplifies the speed control signal c outputted from the speed detector 7. The abnormality signal d of the abnormality detector 16 is transmitted to the amplifier 15 to prevent the speed of the abnormality detector 16 from increasing abnormally.
is input, the output e of the amplifier 15 is set to zero, and the rotation of the DC motor is stopped.

With the above configuration, when the armature winding 4 of the DC motor 1 overheats and there is a risk of burnout, the overheat detector 13 detects this and inputs the overheat signal f to the amplifier 15. The output of the armature winding 4 is made zero to prevent burnout of the armature winding 4. The operation described above prevents burnout of the armature winding 4, but since the overheat detector 13 is placed apart from the armature winding 4, there is a delay in the detection operation of the overheat detector 4. can be,
When the temperature of the armature winding 4 suddenly rises, there is a drawback that sufficient overheat protection cannot be provided. In order to eliminate the delay in the operation of the overheat detector 4, it is effective to attach the overheat detector 13 to the armature winding 10. A slip ring or rotary transformer is required to transmit the signal to the power source, which has the disadvantage of complicating the configuration of the equipment and increasing costs.

The purpose of this invention is to eliminate the above-mentioned drawbacks of the conventional ones.The present invention has an overheat detector installed in contact with the rotor winding, and an output signal of the overheat detector is transmitted to a speed detector. The present invention provides an overheat protection device for a rotating electrical machine that detects overheating of a rotor winding based on an abnormality in a speed signal from a speed detector.

An embodiment of the present invention will be described below with reference to FIG. In the figure, the same reference numerals as in FIG. Armature winding 1
This is a connection line that transmits to 0. In addition, overheating detector 1
If 7 is a normally closed contact, overheat detector 17
is connected in series to the armature winding 10 of the speed detector 7, and if the overheat detector 17 is of a normally open contact type, the overheat detector 17 is connected in parallel to the armature winding 10 of the speed detector 7. .

With the above configuration, when the temperature of the armature winding 4 of the DC motor 1 is below a predetermined temperature, the overheat detector 17 does not operate, so the overheat signal is sent to the armature winding 10 of the speed detector 7. Since f is not transmitted and therefore no change occurs in the speed signal of the speed detector 7, the operation of the DC motor 1 continues as it is.
Next, when the temperature of the armature winding 4 of the DC motor 1 reaches a dangerous temperature that may cause burnout, an overheat detector 17 is activated.
is activated, transmits the overheating signal f to the armature winding 10 of the speed detector 7, and when the overheating load detector 17 is a normally closed contact, the armature winding 10 is opened by opening the contact, and the armature winding 10 is opened normally. In the case of contacts, the closing of the contacts short-circuits the armature winding 10, causing an abnormality in the speed signal in either case. As a result, the abnormality detector 16 operates, and the abnormality signal d from the abnormality detector 16 is transferred to the amplifier 15.
is input, and the output e of the amplifier 15 is set to zero, thereby stopping the DC motor 1 and preventing burnout of the armature winding 4.

In the above embodiment, a contact type was shown as the overheat detector, but it is not limited to this.
For example, a thermistor whose resistance value suddenly changes when a predetermined temperature is reached can be used. Further, as the abnormality detector, it is also possible to use one that detects a disturbance in the waveform of the speed signal due to the operation of the overheating detector. Further, in this case, the amount of feedback becomes oscillatory, and by detecting that abnormal vibration occurs in the DC motor, an overheating alarm can be issued. In the above embodiments, a DC motor is used as the rotating electric machine, but an induction machine having windings wound around the rotor,
The present invention can be similarly implemented in any rotating electrical machine such as a synchronous machine, provided that it is equipped with a speed detector that rotates integrally.

As described above, according to the present invention, since the overheat detector is attached directly to the winding of the rotor, the response operation of the overheat detector becomes faster, and the overheat signal generated by the operation of the overheat detector is transmitted via the speed detector. To provide an inexpensive and highly reliable overheat protection device for a rotating electrical machine without the need for a dedicated device for transmitting an overheat signal such as a slip ring or a rotating transformer. be able to.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a conventional example, and FIG. 2 is a circuit diagram showing the configuration of an embodiment of the present invention. In the figure, the same reference numerals indicate the same or equivalent parts, 3 is an armature, 4 is an armature winding, 7 is a speed detector, and 13 and 17 are overheat detectors.

Claims (1)

[Claims] 1. In an overheat protection device for a rotating electric machine equipped with a speed detector that is connected to a rotor around which windings are wound and rotates integrally, an overheat detector that detects overheating of the winding is connected to the rotor. The rotation is characterized in that it is attached in contact with a winding, transmits an output signal of the overheat detector to the speed detector, and detects overheating of the rotor winding based on an abnormality in the speed signal of the speed detector. Overheat protection device for electrical equipment.