Is there a problem if a motor with a rated voltage of 690V is used in a 400V voltage system?
Thread Content
Is there a problem if a motor with a rated voltage of 690V is used in a 400V voltage system?
It works fine without a load, but not when under the rated load!
The motor cannot operate at a voltage lower than 70% of its rated voltage, as this will cause it to burn out; the setting for the motor’s low-voltage protection is 70%
It depends on the application; if used for heavy loads, it may cause the motor to burn out due to stopping.
It cannot be used this way! It should be used at the rated voltage!
Since it is specified as 690V, I think it’s best to supply power at that voltage. Also, these days many motors are specified with 690V/380V, so there should be no problem with that
This post was last edited by zyz8438 on 2010-12-23 at 12:11. Using a 690V motor at 400V is equivalent to operating a motor connected in a triangular configuration in star connection at 690V. The voltage across each winding has changed from 690V to 400V. This can operate under no-load or light-load conditions. However, it cannot operate when the load is high, approaching the original rated load or even exceeding it.
The purpose of setting a low voltage is to prevent a drop in voltage under unchanged load conditions, which could cause overcurrent in the motor windings. Also, from a process perspective, it is necessary to ensure that a backup pump can be quickly switched in in the event of a power failure in one of the pumps. So, from a purely electrical perspective, as long as the motor windings do not experience excessive current flow, there is no problem regardless of how low the voltage is!
The current that the motor winding is designed to handle is fixed, that is, the rated current. However, since the voltage across the windings dropped from 690V to 400V, its rated power also changed at this point, becoming 0.57 times the original rated power. The load-carrying capacity has decreased! However, as long as the load is within 0.57 times the original rated power, the motor can continue to operate.