Motor for VSD
Motor for VSD
(OP)
Hi
Presently, there are few set of pumps(motors) started by softstarters. Due to the changes of application, we need to use VSD instead of softstarter. The contractor explained that motor also need to be replaced as current motor(s) is not suitable for the VSD.
My question here is that is it correct fixed speed motor can not be used as variable speed motor?
I am supposed to ask motor supplier/manufacturer but I would like to hear from other opinion.
Regards
Presently, there are few set of pumps(motors) started by softstarters. Due to the changes of application, we need to use VSD instead of softstarter. The contractor explained that motor also need to be replaced as current motor(s) is not suitable for the VSD.
My question here is that is it correct fixed speed motor can not be used as variable speed motor?
I am supposed to ask motor supplier/manufacturer but I would like to hear from other opinion.
Regards






RE: Motor for VSD
The difference is not "Will it Work?", it's "How Long Will it Work?"
With pumps be aware of forbiden speed ranges. As each vane of an impellor passes the discharge it sends a pressure pulse down the pipe. These pressure pulses can reflect back from an elbow. At certain speeds, the reflected pulses add to the new pulses. This can be cumulative and actually burst a pump casing. A good quality VFD for pump duty will have provision to lock out certain speeds or frequencies.
Baldor Electric suggests that for some applications a non VFD rated motor may be used.
I would suggest calling a reputable motor rewind shop for an evaluation of your needs. At the same time query the feasibility of having some of your existing motors rewound to VFD standards.
yours
RE: Motor for VSD
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Motor for VSD
Regards
RE: Motor for VSD
RE: Motor for VSD
RE: Motor for VSD
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Motor for VSD
As a minimum for variable speed motors in hazardous areas, motor thermistors would need to be connected in order to directly trip the motor on high temperature. Shielded power cable would also be required.
If a zone 1 area, I think that the motor and VSD has to have been certified as a system (ATEX) - i.e. the motor/drive combination will have been tested and approved as a system by the certification body (BASEEFA or equivalent).
Allan
RE: Motor for VSD
Thank you for your inputs. However Pumps are located at non-hazardous area.
Regards
RE: Motor for VSD
Tim Macdonald
Hydro Dyne Inc.