Darin, the issue with the motor you listed is that it's not designed or insulated for vfd service. There's a possibility that it will buzz or vibrate at any frequency other than 60 hz. It could also short out the windings from the vibration.
Variable speed pump install
- Thread starter eskewj
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Dave,
You absolutely may be correct.
But so far that is not my experience. I have 1.5 hp motor in this family/class which has "B" insulation. No buzz up and down from 15 Hz to 60 Hz. No vibration.
Pools are in a clean low dust and grime to stick to the motor so one should not be too concerned about heat dissipation since there is nothing holding heat onto the motor casing. Easy to put a sun shade above it if it is in full sun.
VFD is programmed to not go lower than 15 hertz, and even then only when backwashing/rinse cycle for a few minutes. Normal rate is around 30 hertz and 60 at cleaning.
Have you heard of someone with a motor in this range 0.5 to 1.5 hp that has had this problem? I have not, or i just have not looked in the correct place.
You absolutely may be correct.
But so far that is not my experience. I have 1.5 hp motor in this family/class which has "B" insulation. No buzz up and down from 15 Hz to 60 Hz. No vibration.
Pools are in a clean low dust and grime to stick to the motor so one should not be too concerned about heat dissipation since there is nothing holding heat onto the motor casing. Easy to put a sun shade above it if it is in full sun.
VFD is programmed to not go lower than 15 hertz, and even then only when backwashing/rinse cycle for a few minutes. Normal rate is around 30 hertz and 60 at cleaning.
Have you heard of someone with a motor in this range 0.5 to 1.5 hp that has had this problem? I have not, or i just have not looked in the correct place.
tcat
Silver Supporter
- May 30, 2012
- 1,618
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- 17000
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- CircuPool Edge-40
You're oversimplifying a relatively complex topic in my opinion.
Motors that aren't designed to run at low frequencies are susceptible to heating and vibration effects, particularly in certain parts of the rotor and stator, and derating at the very least should be considered.
Motors meant to be driven by a VFD are constructed considerably differently, there's a reason they are more expensive.
