if VFD MOTOR is ok with standard Soft Start Controller
if VFD MOTOR is ok with standard Soft Start Controller
(OP)
I have Standard Duty Soft Start Drive. However, the submittal for the project specifies VFD Duty motor.
I do not see any problem with Standard Control (RVSS).
Do I miss anything?
I do not see any problem with Standard Control (RVSS).
Do I miss anything?





RE: if VFD MOTOR is ok with standard Soft Start Controller
A soft starter does not subject a motor to the same high voltage transients that a VFD may. That said, a VFD duty motor will be better able to withstand any over voltage transient than a non VFD rated motor.
The engineer spec'ing the project may have a reason for wanting VFD motors even for non VFD drives.
Bill
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"Why not the best?"
Jimmy Carter
RE: if VFD MOTOR is ok with standard Soft Start Controller
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
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RE: if VFD MOTOR is ok with standard Soft Start Controller
Bypassing the VFD after start made it possible to use 'undersized' VFDs, which made the VFD choice easier.
It is possible that the specs were written to cover such cases. Better check with the project manager.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: if VFD MOTOR is ok with standard Soft Start Controller
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(2B)+(2B)' ?
RE: if VFD MOTOR is ok with standard Soft Start Controller
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: if VFD MOTOR is ok with standard Soft Start Controller
There are certain VFD motors that have a modified speed-torque curve that don't play well with soft-starter. In these cases, the locked-rotor and pull-up torque is sacrificed to give more breakdown torque.
These days, most standard motors are built with the same wire insulation regardless of being VFD rated or not. However, I have seen crappy "VFD Rated" motors fail. So, in the end, a "VFD Rated" tag on an otherwise standard induction motor really means very little. There are motor lines specifically built for VFD use. The BlackMAX motor would be one example of this.