drcampbell
Senior Member
- Location
- The Motor City, Michigan USA
- Occupation
- Registered Professional Engineer
Whether it has a fan on the motor shaft is just one of many variables.
But since it's an overhead crane, I'm going to guess that the duty cycle's low enough that heat isn't going to be a big problem.
A VFD will reduce the voltage as it reduces the frequency and limit the current, which should adequately limit the heat and the temperature. If you're worried enough, you could attach a thermocouple to the motor laminations.
One possible concern: Since the motor was originally designed for fixed 60Hz, the stator might not have enough inductance to satisfy the VFD's control strategy at very low frequencies. (again, this is semi-educated guesswork)
But since it's an overhead crane, I'm going to guess that the duty cycle's low enough that heat isn't going to be a big problem.
A VFD will reduce the voltage as it reduces the frequency and limit the current, which should adequately limit the heat and the temperature. If you're worried enough, you could attach a thermocouple to the motor laminations.
One possible concern: Since the motor was originally designed for fixed 60Hz, the stator might not have enough inductance to satisfy the VFD's control strategy at very low frequencies. (again, this is semi-educated guesswork)