JPS63117692A - Control circuit for air conditioning motor - Google Patents

Abstract

PURPOSE:To always effect air conditioning steadily by varying a voltage supplied to a blower upon variation in resistance in and out of the blower to prevent air quantity from decreasing. CONSTITUTION:When a foreign material is adhered to an air filter and resistance of air passages in and out of a blower is increased, the rotating speed of the blower and hence a motor 1 for the blower is reduced, thereby decreasing a blower current flowing to the motor 1. The variation amount of the current value is detected through a detecting coil 5 by a current detector 7, and fed back to phase control means 8. The means 8 varies the firing phase amount of R-, S-and T-phases by this feedback to raise a voltage supplied to the motor 1, thereby increasing its torque. Thus, the rotating speed of the motor 1 is raised to control to increase air quantity.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an air conditioner that performs cooling or heating (hereinafter referred to as an air conditioner), particularly an air conditioner that controls an electric motor used in a blower for a heat exchanger on the user side. This invention relates to a control circuit for an electric motor.

[Conventional technology]

FIG. 2 is a control system diagram of a portion of a conventional general air conditioner. In the same figure, reference numeral 1 denotes an IR electric motor for a blower for driving a blower that forcibly exchanges heat between indoor air and a heat medium in a user-side heat exchanger.

is, IT is R・S-T connected to blower motor 1
Phase power lines, 2a and 2b are control system fuses connected at one end to the R-phase power line LR and S-phase power line tS, respectively; 3 and 4 are connected in series between the other ends of both fuses 2a and 2b. These are the operation relay and operation switch.

The driving relay 3 is an R- connected to the blower motor 1.
8-T phase power supply lines LR, 18, and IT each have a contacts 3a'Th interposed therebetween, which supply and stop power to the blower motor l. Further, the operation switch 4 supplies and stops power to the operation relay 3.

Next, the operation will be explained. When operating an air conditioner,
When the R-8-T phase power is turned on to the main circuit, a voltage is applied between both ends of the fuses 2a and 2b, and when the operation switch 4 is turned on, the operation relay 3 is energized and the a contact 3a is turned on. As a result, the blower electric motor 1 rotates and air conditioning starts.

[Problem that the invention seeks to solve]

Conventional control circuits for air conditioning motors are configured as described above, so that foreign objects in the room adhere to the air filter installed on the airflow path of the blower or on the airflow path, etc., increasing the total resistance inside and outside the machine. Problems such as poor quality of air conditioning, such as cooling or heating, are common.

This invention was made in order to solve all of the above-mentioned problems, and it provides an air conditioning motor that can change the voltage supplied to the blower to alleviate the decrease in air volume, etc., as the resistance increases in the air passages inside and outside the machine. The purpose is to obtain a control circuit for

[Means to solve all problems]

The air conditioning motor control circuit according to the present invention is provided with a phase control means for fully controlling the ignition phase of each phase of the power supply in the main circuit of the blower, and is connected to the blower motor and installed on at least one phase line of nine power supply lines. The current detection means for detecting changes in the current in the line is made of gold film, and the changes in the current value are detected and fed back to the phase control means.

[Effect]

In the air conditioning motor control circuit according to the present invention, the phase control means converts the change in current value detected by the current detection means into a total firing phase change amount, changes the supply voltage to the blower motor, and adjusts the air conditioning power. Make money constant.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, the same reference numerals 1 to 4 as in FIG. 2 are the same or equivalent parts as in the prior art, and their explanation will be omitted. 5 is a detection coil wound around the S-phase power supply line tS between the blower motor l and the a contact 3a, and serves as a current transformer for detecting the current; 6 is a power supply whose primary side is connected in parallel to the operating relay 3; The transformer 7 has each input terminal connected to the detection coil 5 and the secondary winding of the power transformer 6, is supplied with power from the power transformer 6, and is a current detection device 8 that detects the amount of change in current from the detection coil 5. is the R-8- between the a contact 3a and the R-8-T phase power supply.
A phase control means interposed in the T-phase power supply lines IR, is and IT controls the firing phase of the R-8-T phase according to the amount of current change detected by the current detection device 7. 8a is R-8-
A group of thyristors 8b each interposed in the T-phase power supply 2in ta, ts, and t'r and capable of passing current in both directions.
is a phase control circuit that changes the phase of the ignition noculus according to the magnitude of the detection signal from the current detection device 7 and supplies each ignition pulse to each r of the thyristor group 8a. Note that the phase control means 8 is composed of a thyristor group 8a and a phase control circuit 8b.

Next, the operation of this embodiment will be explained. When operating the air conditioner, when the power (AC200V) is turned on to the main circuit of the blower motor 1 of the R-8-T phase, both the
A voltage is generated between 2 a and 2 b. When the operation switch 4t is turned on, the operation relay 3 is excited and voltage is applied to the power transformer 6. Power is supplied to the current detection device 7, and the phase By the ignition phase control by the control means 8, the initial voltage of the main circuit is lowered to a low voltage as follows.

When the operation/use relay 3 is energized as described above, its a contact 3a is turned on, and when the air path resistance is less than the specified value (for example, when an air conditioner is installed), the voltage is about 50%, for example in this embodiment. Power supply voltage is AC200V, so AC100V
The front and rear parts are supplied and the blower electric motor l rotates.

The air conditioner has a certain amount of operation time (for example, 500~too many operating hours)
As time passes), foreign matter adheres to the air filter, etc., and the resistance of the air passages inside and outside the machine increases, so the rotation speed of the blower, that is, the rotation speed of the blower motor 10, decreases, and the blower motor 1
The blower current flowing to the A current detection device 7 detects this change in current value through all of the detection coils 5, and feeds it back to the phase control means 8. Based on this feedback, the phase control means 8 changes the ignition phase amount of the R-3-T phase, increases the voltage supplied to the blower motor 1, increases the torque, and increases the rotation limit of the blower motor 1. Perform control to increase air volume.

Further, although this embodiment has been described for controlling a blower of an air conditioner, the same effect as in the above embodiment can be obtained also for controlling a protection circuit for overcurrent detection.

〔Effect of the invention〕

As described above, according to the present invention, the phase control means is provided in the main circuit of the blower motor, and the operation of the phase control means is controlled by detecting changes in the current flowing through the blower motor. As a result, the supply voltage of the blower is completely changed to prevent the air volume from decreasing due to resistance changes inside and outside the machine, which alleviates problems such as poor air conditioner performance, and by setting the initial voltage low, the blower This has the effect of reducing the input power of the electric motor, leading to energy savings.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an air conditioning motor control circuit showing an embodiment of the present invention, and FIG. 2 is a conventional control system diagram. In the figure, l...Blower electric motor, IR, 18°I
T...Power line, 5...Detection coil, 7...Current detection device, 8...Phase control means. In addition, in the figures, the same symbols indicate the same or equivalent parts〇

Claims (1)

[Claims] A user-side heat exchanger for exchanging heat between indoor air and a heat medium, a driving electric motor used for a blower for forcing the user-side heat exchanger to exchange heat by blowing air, and a drive electric motor connected to the electric motor. The air conditioner has a plurality of power supply lines for supplying power, and is configured to harmonize the temperature of the indoor air through heat exchange, the air conditioner having a coil attached to at least one phase of the power supply line. and a current detection means for detecting a current change in the at least one phase line caused by a load change of the electric motor, and a thyristor group interposed in the power supply line, and a feedback signal from the current detection means. A control circuit for an air conditioning motor, comprising: phase control means for changing the phase of the firing pulse to the gate of the thyristor group in accordance with the magnitude of the thyristor group to change the supply voltage supplied to the motor.