What if he doesn't wear one?Your slip will make that a little lower.
Yes, but the OP only asked about speed...Maybe its obvious, but voltage must lowered accordingly.
True but isn't it incumbent upon us, as professionals, to offer relevant advice?Yes, but the OP only asked about speed...
True but isn't it incumbent upon us, as professionals, to offer relevant advice?
True but, in this case, I think it is a relevant and important bit of information to pass on to the op.Of course it is but we also sometimes need to remember not to swamp people with too much info and overwhelm them. I know I am guilty of doing it at times.
True but, in this case, I think it is a relevant and important bit of information to pass on to the op.
True but, in this case, I think it is a relevant and important bit of information to pass on to the op.
the voltage does not affect the speed.
Maybe its obvious, but voltage must lowered accordingly.
Thanks for help. If we lower the Hz we also need to adjust the voltage? The pump is a 480v 3phase small injector pump that feeds a clarifier for a water plant. The customer keeps the vfd to 20.9 hz I was wondering what other issues this causes to pump by controlling speed with Hz. Thanks for any help
Correct, the voltage at the motor should be around 160 volts for 20hz, otherwise the motor will run hotter- burning up if the voltage is high enough. The ratio V/Hz should be 7.5-8. In other words the voltage when divided by your actual frequency should always be around 7.5.QUOTE]
I really do appreciate the help and answers. but how do you lower the voltage? from 480v to 160v does the vfd do that also. Like I mentioned I dont have much experience with vfd I just want to understand the process. I will read the link you shared
Correct, the voltage at the motor should be around 160 volts for 20hz, otherwise the motor will run hotter- burning up if the voltage is high enough. The ratio V/Hz should be 7.5-8. In other words the voltage when divided by your actual frequency should always be around 7.5.QUOTE]
I really do appreciate the help and answers. but how do you lower the voltage? from 480v to 160v does the vfd do that also. Like I mentioned I dont have much experience with vfd I just want to understand the process. I will read the link you shared
It should do it automatically. Otherwise it wouldn't be a good VFD. Jraef would know more regarding that however.
That’s exactly what a BFD does, alter the voltage and frequency together to maintain the same ratio of V/Hz that the motor was designed for. So if the motor nameplate says 460V 60Hz, that’s 7.6 V/Hz (460/60). So as you change the frequency reference to change the speed, the BFD changes the voltage at the same time. So long as you maintain that same V/Hz ratio, the motor can produce it’s rated torque at any speed without causing over or under saturation of the windings, so no harm to the motor (in theory). There are more little nuances as you get into the details of course.
BFD? Big Freaking Device?
Fat fingered the key board....!