How can we achieve the purpose of controlling the two speed motor by measuring the temperature?

What you mean is that you want to adjust the motor speed by measuring the temperature of the two-speed motor, that is, switching the number of poles of the motor when the motor temperature reaches a certain value. For the motor itself, there is no such function, we need to add auxiliary equipment, such as a control box or PLC composed of relays, which we collectively refer to as the control unit. First of all, we need to set a temperature limit value for the control unit, that is, a switching critical point, when the temperature sensor transmits electrical signals to the control unit to reach the critical point, the control unit performs an operation that was previously changed manually, such as changing the number of poles of the motor as you mentioned.

Manually changing the number of poles of the motor is only an operation on the stator coil terminal in parallel, which can be performed manually, and the control unit can also be designed, just to design a logic.

It is a thermistor sensor, and the three are placed in the three-phase winding part of the motor and connected in series.

He selected the model according to the insulation grade of the motor, and the winding temperature reached the upper limit of the thermistor, and the resistance value of the thermistor rose sharply, with the matching overheat protector. Cut off the power and give an alarm.

The resistance of PT100 varies linearly with temperature, which is proportional. Unlike thermistors, the resistance has a sharp turn.

Use a 2-stage temperature control instrument. Set your temperature to 2 stages, heating is the motor is the first speed, and when the temperature reaches the temperature of the 1 stage, the output contact is the second speed when the output contact is connected to the two-speed motor. The meter automatically jumps to the second stage and continues to heat!

Your problem should be solved. The key is the instrumentation issue. The market has.

The motor itself cannot have its own controller, just add the control unit, the so-called control unit, is how we want him, and then according to our ideas to achieve him.

The motor itself cannot have its own controller, and it is generally switched through contactor control, and the contactor can be controlled by PLC.

Make use of temperature sensors.

And use an inverter to convert its signal to 4-20 mA.

After connecting the inverter control terminal.

The inverter is connected to the motor, so that when the temperature rises, the sensor output decreases and the motor slows down; When the temperature decreases, the sensor output increases and the motor accelerates, thus achieving your control purpose.

First of all, the thermostat should be connected to the thermocouple.

Or a RTD thermometer.

connected, from where the temperature data is obtained;

Secondly, the thermostat should set the range of temperature control, as low as how many degrees to start, as high as how many degrees to stop, or vice versa. Then judge what action should be taken based on the information provided by the thermometer;

The thermostat and the inverter are then connected and the measures are passed on to the inverter to make it respond;

Finally, the inverter controls the motor to run at low speed, high speed or stop running.

For example, the air conditioner is set to 25 first, and the thermostat is set to plus or minus 1° or another control range, and when the temperature exceeds (below or above) the range, a signal is sent to the inverter to control the motor to run at low speed and high speed, or stop, so that the indoor temperature is always in a comfortable range.

If your thermostat has an analog output, and your inverter can be controlled by analog, you can connect the two and set it up.

This requires a complex system. It depends on how your thermostat outputs the signal, and how the inverter receives the signal. and the logical handling of control.

Use the temperature sensor and use the inverter to convert its signal into 4-20 milliamperes, and connect the inverter control terminal to connect the inverter to the motor, so that when the temperature rises, the sensor output decreases, and the motor slows down; When the temperature decreases, the sensor output increases and the motor accelerates, thus achieving your control purpose.

It depends on the type of motor you have first. If it is an ordinary asynchronous motor. What is needed is a frequency converter. The speed regulation of the frequency converter may be regulated by the output of the thermostat.

Use the temperature sensor and use the inverter to convert its signal into 4-20 milliamperes, and connect the inverter control terminal to connect the inverter to the motor, so that when the temperature rises, the sensor output decreases, and the motor slows down; When the temperature decreases, the sensor output increases and the motor accelerates, thus achieving your control purpose.

If the speed change you require is not very large, you can directly use voltage regulation to adjust the speed, the system is simple: use an XMTD temperature control meter, use it to control the upper and lower limits of temperature, and then use the voltage regulating solid state relay to adjust the voltage to the motor according to different upper and lower limit requirements, so as to achieve your requirements. These are readily available in the market.

If you require a large variation in speed, or a DC motor type, this can also be achieved, but in this case it will be necessary to use a more complex system to control. Because you don't have clarity, you won't say much.

l Use the temperature sensor to convert its signal to 4-20 mA in connection with the external terminal of the inverter The inverter is connected to the motor, and it can be directly controlled, ** The air conditioner is controlled in this way, and the large hotel is to transmit the signal to the inverter through the temperature sensor of the room, and the inverter automatically controls the speed of the fan to achieve the temperature of the room.

Temperature Sensors, Temperature Signal Conversion Modules, Inverters.

The speed regulation of the three-phase asynchronous motor can be obtained by changing the input voltage frequency (frequency conversion speed regulation), pole change speed regulation and variable slip rate speed regulation.

These three methods are based on the formula N=(1-S)60F p, where n is the motor speed, s is the slip rate, f is the frequency, and p is the number of pole pairs.

As long as the above speed regulation is passed, the corresponding speed can be obtained, and these can be obtained through the circuit, or electrical appliances.

Change its control circuit, first of all, you look at the junction box of your motor's main motor, it should be nine selling fiber wires! Tanner is observing that the kind of connection is a high-speed and low-speed imitation!

I am trying to control it with a contactor!

The volume of the inverter is not very large! You can fix it with a few holes, but you have to pay attention to dustproof!

The working principle of the two-speed motor is to change the number of pole pairs of the stator to change the speed of the motor, the speed of the motor is inversely proportional to the number of pole pairs, when the number of pole pairs is doubled, the speed drops by half, otherwise otherwise, the purpose of speed regulation is achieved.

The number of stator pole pairs can be changed by changing the wiring method of the stator winding, and the key is that the current in the stator winding of each phase changes direction. The commonly used wiring is: Y to yy, change to yy and along the string Y - reverse string Y these three connections.

Electrician knowledge: the working principle of the two-speed motor, the 15-minute wiring steps are explained one by one, and the operation is demonstrated.