Moror Overloads

[dmulhol925]

When setting motor overloads, is it 125% of full load amps?

 

[petersonra]

When setting motor overloads, is it 125% of full load amps?

430.92

 

[mayanees]

430.32

 

[ritelec]

MOROR???

MOROR???

I can't find anything about rating overload protection for a moror in those articles.........

Maybe I have a different book................. :huh:


I'll keep looking..

(just playing, have a great one)

 

[kingpb]

To properly select motor overload protection you need to review the thermal damage curves provided by the manufacturer.

The NEC is not the place to find this information.

 

[mjf]

I can't find anything about rating overload protection for a moror in those articles.........

Maybe I have a different book................. :huh:


I'll keep looking..

(just playing, have a great one)

It's a typo......He meant MORON overload......I have one of those everyday!!

 

[petersonra]

III. Motor and Branch-Circuit Overload Protection

430.32 Continuous-Duty Motors.
(A) More Than 1 Horsepower. Each motor used in a
continuous duty application and rated more than 1 hp
shall be protected against overload by one of the means
in 430.32(A)(1) through (A)(4).
(1) Separate Overload Device. A separate overload device
that is responsive to motor current. This device shall be selected
to trip or shall be rated at no more than the following
percent of the motor nameplate full-load current rating:

It really is found in 430.32 as another poster pointed out, and not 430.92 as I said. Weird typo.

 

[Jraef]

It really is found in 430.32 as another poster pointed out, and not 430.92 as I said. Weird typo.

You absolutely MUST read the manufacturers instructions on setting the OL relay or selecting the heater elements (as the case may be). Some manufacturers tell YOU to factor in the 125%, some tell you they have ALREADY factored that in, and you MUST set/select based on the motor nameplate FLC. If you have one that is ALREADY factoring in that 125% pickup point, and you do it AGAIN, you will lose your motor if there is an overload.

 

[iceworm]

You absolutely MUST read the manufacturers instructions on setting the OL relay ....

Yes absolutely agree. Some have instructions that appear to be deliberatly written to defy interpretation. Currently the AB E3 holds that record if one is attempting to set the OVLD at 130% or 140%.

And will be additional instructions to deal with different ambient between the motor and starter.

ice