What risk is associated with the application of full voltage on a DC motor when it is stationary? What are the possible mitigating techniques to the problem?
Also, what is the problem associated with the armature reaction and what could be the solution?
Thanks.
Or use PWM to ramp up the motor speed while limiting startup current.
Or use a Thyristor, and by its phase angle control increase the voltage gradually up to reaching the full motor speed. For non repeated Stop-Run operation of the motor, the mentioned approach is simple, thus cheap, and reasonable. However, at low output voltage of the converter the power factor is low and thus the efficiency is low. According to the application, in case the motor will have a repeated Stop-Run operation cycle, the PWM is better, as the power loss will be less. One factor to consider as well, is the switching loss when a PWM is used.
Yes, an SCR thyristor is not suitable to regulate the voltage if it is already DC. To regulate a DC voltage the best approach is using PWM/class D type operation in the process which is called the DC-DC chopping. However, when the source is AC, half-wave and full-wave controlled AC-DC converters (Controlled rectifiers) are usually used in the applications that require a controlled DC voltage. Correction is welcome.
What kind of motor is it: brush type or electrically commutated? A stalled brush motor could burn out very quickly while a stalled brushless motor could survive until fault detection (if it exists) could kick in.
Another mitigation technique may be current limiting.
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