Motor run
Motor run
(OP)
If would like to run the 480V, 60Hz, 780kw, 1137A, 1791r/min motor to 400V, 50hz.
How will it affect the speed, out-power delivered by motor, current drawn by the motor and torque.
Can anybody please help with that?
How will it affect the speed, out-power delivered by motor, current drawn by the motor and torque.
Can anybody please help with that?





RE: Motor run
RE: Motor run
Your question is very basic. Don't do it! you will let out the magic smoke. Is it a dual voltage motor? Give all the data plate details, is it driven by VFD?
Chuck
RE: Motor run
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Motor run
Dang Jeff! I was under the assumption to not increase or decrease the voltage no more than 10%. Well I stand corrected now and need to dig into some books to understand better. I am not doubting you! Just need more education on this side of the key board. The lower voltage coupled with lower frequency I was thinking less cooling and more current. Time to read some when I get off work.
Chuck
RE: Motor run
480 Volts at 60 Hertz is an 8:1 Volts per Hertz ratio.
400 Volts at 50 Hertz is an 8:1 Volts per Hertz ratio.
As jraef said;
"Torque and current will remain roughly the same, speed will drop to 5/6 of rated, speed will drop to 5/6 of rated, which will affect the kW rating at the shaft,"
I would add that 400V is 5/6 of 480V and the electrical kW consumption will drop by about the same ratio as the mechanical kW.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Motor run
A decrease of 299 rpm, 5% less locked rotor current, and 650 Kw instead of 780 Kw, and since current drop is negligible replacement of overloads is unnecessary.
Chuck
RE: Motor run
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington