# Dual speed motor... how do you get different speeds?



## Flyingsod (Jul 11, 2013)

Breakfasteatre said:


> We have this motor, the nameplate shows two different speeds, 1725 and 1425.
> 
> of course the model number and cat number doesnt come up with anything useful
> 
> ...


Hertz Prolly. One is for us 60hz the slower is for EU 50hz

Sent from my C6725 using Tapatalk


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## Big John (May 23, 2010)

You have two winding configurations and contactors that close to energize one winding versus the other.


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## Breakfasteatre (Sep 8, 2009)

From what ive gathered, the two speeds are achieved by providing either a 60hz or 50hz source, although from that nameplate, it looks like it says 60hz for both speeds. Thats what was confusing


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## Breakfasteatre (Sep 8, 2009)

Big John said:


> You have two winding configurations and contactors that close to energize one winding versus the other.



If you check out the nameplate picture, there is only one winding config. 

From what ive been told, it is a hz thing,as this motor is a single speed motor. 50hz produces the slower speed


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## oliquir (Jan 13, 2011)

thats weird, never seen a 575v 50hz source yet. ive seen 480v 60hz / 400v 50hz versions


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## micromind (Aug 11, 2007)

The top right hand side of the nameplate lists HZ......60......50. Everything under the 60 is data for 60HZ and everything under the 50 is for 50HZ. 

The column you use depends on the HZ or you power supply system. 

Also, as noted, I've never seen 575 50HZ. In my opinion, Leeson is one of the top motor manufacturers but they do strange things with their nameplates sometimes. I suspect the 50HZ rating is the result of a battle of egos between engineers more than anything else. 

The fact that it'll run on 575 at both 50 and 60 HZ tells me that it's pretty well built. A cheap motor won't be able to tolerate the difference in HZ at the same voltage.


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## emtnut (Mar 1, 2015)

micromind said:


> The top right hand side of the nameplate lists HZ......60......50. Everything under the 60 is data for 60HZ and everything under the 50 is for 50HZ.
> 
> The column you use depends on the HZ or you power supply system.
> 
> ...


That's what I thought too ... but I looked at the pic 5 times, and see '60' on both ratings ! ??

Friggin old eyes :no:


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## micromind (Aug 11, 2007)

emtnut said:


> That's what I thought too ... but I looked at the pic 5 times, and see '60' on both ratings ! ??
> 
> Friggin old eyes :no:


Man, I hear ya.........lol.

I actually couldn't see the 50 but I've worked with enough motors by now to be able to guess what it was. 

Whenever I need to read something closer than about 18", I need my glasses. Sometimes it's really annoying........lol.


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## Frank Mc (Nov 7, 2010)

emtnut said:


> That's what I thought too ... but I looked at the pic 5 times, and see '60' on both ratings ! ??
> 
> Friggin old eyes :no:


Me too and thats with my glasses on lol!!!

Frank


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## MCasey (Dec 7, 2016)

emtnut said:


> That's what I thought too ... but I looked at the pic 5 times, and see '60' on both ratings ! ??
> 
> Friggin old eyes :no:


The figures on the right look more like 50 than the left and I have good eye sight.


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## MechanicalDVR (Dec 29, 2007)

Not sure what is up but when I put the catalog and model number in the Leeson site there is no match.


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## John Valdes (May 17, 2007)

micromind said:


> Man, I hear ya.........lol.
> 
> I actually couldn't see the 50 but I've worked with enough motors by now to be able to guess what it was.
> 
> Whenever I need to read something closer than about 18", I need my glasses. Sometimes it's really annoying........lol.


I thought it was 60 and 60 too! Still looks like 60 and 60. 



MechanicalDVR said:


> Not sure what is up but when I put the catalog and model number in the Leeson site there is no match.


Most likely an OEM special build. Not a catalog motor.
To get info on this motor, one must contact a Leeson distributor or Leeson. 
Leeson will then tell the distributor or customer its special and provide a phone number for the OEM.
Then the distributor or customer will call the OEM and get a price.
The distributor or customer will try to cross this to a stock motor because the OEM wants a fortune for the motor.

Best part is its on a standard frame. More than likely the end user will have 60hz or 50hz and not care about the dual HZ rating.
The motor then will be crossed to a stock/on shelf motor.
This does happen. But sometimes the motor could be quite special and require the OEM purchase.
But the frame number is standard and that tells me it can be crossed to a motor on the shelf. Any brand.


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## Jhellwig (Jun 18, 2014)

1425rpm is not a valid 60hz speed. When a motor lists two speeds and o e of them is not close to a 60hz synchronus value you are looking at a 50hz speed.


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## AK_sparky (Aug 13, 2013)

I've worked with a few motors that run on 50 and 60 Hz, but usually it's something like 575V/60Hz and 480V/50Hz. The 575V/50Hz is definitely interesting; I would love to know the back story!


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## buffalonymann (Dec 25, 2016)

Motor speed formula = Srpm=(120)(f)/N. of poles. Do the math - 1725 is the speed for 60hz and 1425 is the speed for 50hz. Remember squirrel cage motors cannot and do not run at synchronous speed, slip is required and that's why they don't run at 1800 rpm and 1500 rpm


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