For torque motors such as ETEL motors, they have particularly high performance in compact designs. However, in certain processing situations, if the current distribution in the winding becomes asymmetric, it will cause sudden temperature fluctuations in the individual winding outgoing lines, and overheating will be a risk. So, digitizing the information of the thermal sensor near the application and transmitting it to the CNC system can provide intelligent motor protection function for high process reliability, while also improving the reliability and efficiency of the machining process.
At this point, to determine whether the motor is starting with reduced voltage, at least three factors must be considered: motor power, transformer capacity, and existing load, none of which are indispensable! So let's take a look at various so-called judgment methods nowadays, have we taken all three into account?
How to comprehensively consider these three factors? For the convenience of using current as a parameter. The essence of this question is: how much current is it? How much voltage drop will it cause? That is, the issue of current and voltage drop.
Everyone knows that the starting current of a cage motor is 5-7 times the rated current.
For transformers, what is the load current that causes electricity
In fact, the main purpose of using step-down starting is to avoid affecting the normal operation of other equipment. If there are no other equipment, only transformers and motors, then the power of the motor can be close to the capacity of the transformer. Considering factors such as power factor and efficiency, the general motor power is 80% of the transformer capacity, and can be started directly, or the transformer and motor can be started simultaneously.
In reality, when the vast majority of large motors start, there are more or less other loads on the transformer, so the amount of other loads also needs to be considered as one of the factors.
Why does starting an electric motor affect the operation of other electrical equipment?
Because the starting current of a cage motor is 5-7 times its rated current, a large current can cause a large voltage drop. If the voltage drop reaches a certain value, other electrical equipment may stop working or cause faults. Therefore, there are regulations that the voltage drop caused by frequent starting of motors should not exceed 10%, and the voltage drop caused by infrequent starting should not exceed 15%.
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Signal input
Signal type: Transistor (PNP&NPN compatible)
NPN signal level (input): NPN: 0-5VDC
PNP signal level (input): PNP: 15-30VDC
Single channel consumption current: 5mA
Port protection (input): overvoltage impact protection
Input characteristics: NPN/PNP (compatible)
Electrical isolation: AC 500V
signal output
Signal type: relay
Rated level: relay 250VAC/30VDC
Single channel rated current: Relay: 5A
Port protection (output): overvoltage and overcurrent protection
Electrical isolation: AC 500V
General parameters
Protection level: IP20
Working temperature: 0-55 ℃
Storage temperature: -25~85 ℃