rated voltage for feeding 4000 V motor
rated voltage for feeding 4000 V motor
(OP)
Hi all,
I don´t use to work under ANSI standard but IEC so I need your help to understand several ANSI considerations. ANSI Requirements for feeding MV motor is:
- grid rated voltage: 4160 V
- motor rated voltage: 4000 V
Does it mean that 4000 V motors are to be fed at 4160 V at rated conditions so the motor would work under "overvoltage" condition continously?. When motor supplier is going to give the tipical motor curves at 100% and at 80% of the rated voltage, these curves must be provided at 4160/3328 V or 4000/3200 V.
What would be the normal operating values for an ANSI grid (i.e if I supply a 4160/480 V transformer, without changing the taps, the operating voltage at LV bus(480 V) when LV motors and LV loads are working, will drop, so the operating LV value will not be 480 but around 460 aprox. Is this the reason why LV motor rated voltage is 460 V to be use in a 480 V grid?
thank you so much in advance
I don´t use to work under ANSI standard but IEC so I need your help to understand several ANSI considerations. ANSI Requirements for feeding MV motor is:
- grid rated voltage: 4160 V
- motor rated voltage: 4000 V
Does it mean that 4000 V motors are to be fed at 4160 V at rated conditions so the motor would work under "overvoltage" condition continously?. When motor supplier is going to give the tipical motor curves at 100% and at 80% of the rated voltage, these curves must be provided at 4160/3328 V or 4000/3200 V.
What would be the normal operating values for an ANSI grid (i.e if I supply a 4160/480 V transformer, without changing the taps, the operating voltage at LV bus(480 V) when LV motors and LV loads are working, will drop, so the operating LV value will not be 480 but around 460 aprox. Is this the reason why LV motor rated voltage is 460 V to be use in a 480 V grid?
thank you so much in advance





RE: rated voltage for feeding 4000 V motor
120 V, 240 V, 480 V and 600 V.
Standard motor rated voltages are multiples of 115 Volts.
115 V, 230 V, 460 V and 575 V.
This is to allow for voltage drops in the feeders and motor circuit conductors.
For many years 230 Volt motors were operated on 208 Volt systems which are quite common for commercial installation. Now, we are seeing 200 Volt rated motors and 208 Volt rated motors for 208 volt systems.
The rated motor voltage is used for specs.
Others with more specific experience with 4160 Volt installations will post in.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: rated voltage for feeding 4000 V motor
Motor performance curves would always be per NAMEPLATE voltage, so 4000V in your case (we never use the Y voltage for motors).
A good explanation of the basic concept can be read here in an excerpt from "Energy Matters", a publication of the US Dept. of Energy. They provide a decent chart of what to expect at the different ranges of terminal voltage.
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RE: rated voltage for feeding 4000 V motor