# Pre Nema Motor



## Handasee (Dec 18, 2009)

I would like to know if the current draw on this motor is within reason.
I don't know if the nameplate information is correct.
Motor is a 2 speed, constant Torque. 
Measured the current draw of 7 amps on slow speed and 2 amps on high speed.
Motor is a GE model 5K324A484 
Name plate information as follows: Type K. 440 volts. Amps 5 and 5. HP 4 and 4, 3ph, 60Hz, speed 600/1200, Form 324, 60hz, 
Connection: low speed power to 6,4,5- 1,2,3 joined
high speed power to 1,2,3- 4,5,6 open
Drawing says: year of mfg 1932
Problem1- I would of expected to see 25 hz not 60 hz for a motor in 1932
Problem2- Modern constant torque motors have low speed connection of 
power to 123, 456 open. high speed power to 645, 123 joined.
Problem3- Both speeds have same HP and same Amperage. 

Had to replace the contactors since they malfunctioned. 
Machine is running now. Just did not expect to see a difference in motor current draw from what the name plate says. 
Anyone seen this before?


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## Vintage Sounds (Oct 23, 2009)

You must be from southern Ontario(Niagara?) if you expected to find a 25 Hz motor from that era.


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## telsa (May 22, 2015)

600 rpm without a gear drive = a whole lot of magnetic poles in its windings.

What is its load?


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## telsa (May 22, 2015)

Handasee said:


> I would like to know if the current draw on this motor is within reason.
> I don't know if the nameplate information is correct.
> Motor is a 2 speed, constant Torque.
> Measured the current draw of 7 amps on slow speed and 2 amps on high speed.
> ...


Torque is going UP as the RPMs drop. 

*POWER* is CALCULATED from torque and RPM, by the following equation: 

*HP = Torque x RPM ÷ 5252 [ foot-pounds system -- a constant ]*

So, your torque doubled as the effective poles jumped from 6 to 12...
And your RPMs dropped in half as the effective poles jumped from 6 to 12.

3.600 RPM ( 2 pole motor ) ==> 600 RPM ( 2x6= 12 pole motor ) (@ 60 Hz)

What's weird is to still see this beast in running condition...

And its size is puny for such a complicated winding. 

600 RPM implies that it's salient wound, to boot. But is it?


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## JRaef (Mar 23, 2009)

> Problem1- I would of expected to see 25 hz not 60 hz for a motor in 1932


25Hz was rare even when it was first used, near Niagara Falls (and New Orleans by the way) at the turn of the century. By the 1930s we had pretty much settled on 60Hz everywhere else.



> Problem2- Modern constant torque motors have low speed connection of
> power to 123, 456 open. high speed power to 645, 123 joined.


Maybe so, but irrelevant. There are many ways to skin this cat and NEMA didn't exist in 1932, so they may have done it differently. Doesn't matter what came along as a later standard though, it is what it is.


> Problem3- Both speeds have same HP and same Amperage.


Torque and current are virtually synonymous, so if designed as a constant torque motor, I would expect the current to be the same. Not the HP however, because HP is a combination of torque and SPEED. So if your torque is the same, but your speed is 1/2, your HP is 1/2. So that part of this story is the only one that doesn't make sense. Might have been a mistake, or maybe, in the days before STANDARDS saying what you put on a nameplate, someone was interpreting that the nameplate HP should reflect the MAXIMUM HP the motor is capable of, even though that would technically only be at the high speed.


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## telsa (May 22, 2015)

JRaef...

I'd say the label is all garbled.

Instead of constant torque -- I'd say that this motor is constant RPM. 

( 600 rpm == ~ salient pole design? 

[ "projected pole" ? "...for low load torque, has flats ground onto a conventional squirrel-cage rotor to create discrete poles." Wiki ) 

12 poles figure to make it a very high torque motor, invariant rotary speed -- almost -- as the load is pumped up. ( The current draw taking off with increased load. )

The flat amperage rating (5 & 5) makes perfect sense if the pole count is changed to get the speed changed. ( Again, per the formula, op cit above )

It is intended for constant speed usage where its load will scarcely change: such as a (horizontal) conveyor system. In such an application, it will have both properties, running virtually steady state at 5 amps. ( A canning line comes immediately to mind. )

With so many poles, constant torque is not the term that leaps to my mind. (Torque saturated/ torque LIMITED are more understandable.

As one might imagine, should the conveyor system become jammed -- the design favors a motor that stalls/ slips before real damage is done. 

Suddenly, dinky draw of this (exotic) motor makes perfect sense.

But, what can you expect from a 1932, pre-NEMA label.


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## JRaef (Mar 23, 2009)

> Connection: low speed power to 6,4,5- 1,2,3 joined
> high speed power to 1,2,3- 4,5,6 open


I just looked, this IS the standard NEMA configuration for a 2 speed 1 winding constant torque motor. 
https://www.joliettech.com/easa-ele...winding-easa-electrical-engineering-handbook/

The torque and current will be constant, the low speed will be 1/2 of the high speed, and so will the HP. So like I said, the only thing that does not fit is the nameplate saying the HP is the same at both speeds, which doesn't make sense.


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## Handasee (Dec 18, 2009)

JRaef said:


> I just looked, this IS the standard NEMA configuration for a 2 speed 1 winding constant torque motor.
> https://www.joliettech.com/easa-ele...winding-easa-electrical-engineering-handbook/
> 
> The torque and current will be constant, the low speed will be 1/2 of the high speed, and so will the HP. So like I said, the only thing that does not fit is the nameplate saying the HP is the same at both speeds, which doesn't make sense.


 This motor is reversed to what it says in the handbook. 
Connection: *low speed* power to 6,4,5- 1,2,3 joined
*high speed* power to 1,2,3- 4,5,6 open


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## Handasee (Dec 18, 2009)

This motor is mounted on a Farrel 2C Gear Cutter (Sykes gear Generator).
made by Farrel-Birmingham Company in Buffalo NY.
This picture is *not* the exact machine but looks close to the machine I was working on.


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