snipped

-Keep the 575 volt motor, get a 240 to 480 volt step-up transformer and
480 volt variable frequency drive (VFD), and tell the VFD it's driving a
50 Hz motor. You'll lose 1/6 of your horsepower, but otherwise
everything will be fine.


snipped

Ned Simmons

Ned,
I understand about the 1/6 power loss due to running the 575V motor off 480V , but why tell the VFD it's a 50 cps. motor? I thought Canada was the same as the US, 60 cps. line voltage?

Garrett Fulton fired this volley in
:



snipped

-Keep the 575 volt motor, get a 240 to 480 volt step-up transformer
and 480 volt variable frequency drive (VFD), and tell the VFD it's
driving a 50 Hz motor. You'll lose 1/6 of your horsepower, but
otherwise everything will be fine.


snipped

Ned Simmons

Ned,
I understand about the 1/6 power loss due to running the 575V motor
off 480V , but why tell the VFD it's a 50 cps. motor? I thought
Canada was the same as the US, 60 cps. line voltage?




I personally think it's a fool's errand. Those motors - in that form-
factor, are available new and rebuilt in 230V ratings. They're not all
that costly.

Lloyd

On Sun, 22 Mar 2015 16:32:30 -0700 (PDT), Garrett Fulton
wrote:



snipped

-Keep the 575 volt motor, get a 240 to 480 volt step-up transformer and
480 volt variable frequency drive (VFD), and tell the VFD it's driving a
50 Hz motor. You'll lose 1/6 of your horsepower, but otherwise
everything will be fine.


snipped

Ned Simmons

Ned,
I understand about the 1/6 power loss due to running the 575V motor off 480V , but why tell the VFD it's a 50 cps. motor? I thought Canada was the same as the US, 60 cps. line voltage?


That thread's old enough that I don't remember writing that, but I can
explain it. Simple open loop VFDs are often called volts/Hz drives
because they adjust their output to maintain the voltage to frequency
ratio constant as the frequency changes, which in turn keeps the motor
current more or less constant. So if you tell the drive the motor's
nameplate says 480V / 50Hz, the drive will output 480V at 50Hz,
instead of the default (in the US) 480V at 60Hz.

480/50 = 575/60

--
Ned Simmons

On Sunday, March 22, 2015 at 9:07:34 PM UTC-4, Ned Simmons wrote:
On Sun, 22 Mar 2015 16:32:30 -0700 (PDT), Garrett Fulton
wrote:



snipped

-Keep the 575 volt motor, get a 240 to 480 volt step-up transformer and
480 volt variable frequency drive (VFD), and tell the VFD it's driving a
50 Hz motor. You'll lose 1/6 of your horsepower, but otherwise
everything will be fine.


snipped

Ned Simmons

Ned,
I understand about the 1/6 power loss due to running the 575V motor off 480V , but why tell the VFD it's a 50 cps. motor? I thought Canada was the same as the US, 60 cps. line voltage?


That thread's old enough that I don't remember writing that, but I can
explain it. Simple open loop VFDs are often called volts/Hz drives
because they adjust their output to maintain the voltage to frequency
ratio constant as the frequency changes, which in turn keeps the motor
current more or less constant. So if you tell the drive the motor's
nameplate says 480V / 50Hz, the drive will output 480V at 50Hz,
instead of the default (in the US) 480V at 60Hz.

480/50 = 575/60

--
Ned Simmons

Okay. I understand. Thanks for the time.