Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
(OP)
I would like to rewind an old induction motor (squire cage rotor) from 25 Hz to 60 Hz. Is this transformation possible? Thank you very much.





RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
That has puzzled me ever since. And now, you actually have one of those 25 Hz induction motors.
May it be that it is from upstate NY? In that case, don't change anything. Keep that antique motor as is and buy a new motor instead. Even if a rewind probably is possible (you need to think about the 2.4 times higher speed, or change number of poles) it will probably cost more than a brand new motor and you will still end up with an inferior machine.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
In my patch of the world we had legacy 40Hz systems in some of the chemical plants until fairly recent times. The plants used huge rotary frequency changers to supply their private networks. I believe that last of these retired within the last 10 - 15 years.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Right now, we are working with 16.7 Hz (or 16 2/3 Hz - there IS a difference) systems. Heavy transformers...
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Years later I worked in a small refinery in Toronto and in an old disused part of thw plant there were a number of motors dating back to the big changeover with the tags still attached.
Google gives these results:
Amtrak's 25 Hz traction power system
http://en.wikipedia.org/wiki/Amtrak%27s_25_Hz_trac...
Rankine Generating Station Shut down in 2006
http://www.technology.niagarac.on.ca/people/mcsele...
25-Hz at Niagara Falls
end of an era on the Niagara Frontier, part I
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&...
Harnessing Niagara Falls:
The Adams Power Station
The most famous of early hydroelectric power stations
http://edisontechcenter.org/Niagara.htm
OPG powers down generating station
http://www.timminspress.com/2010/03/01/opg-powers-...
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
I'm not sure what happened on that once my contractor was out of the running, but I think they may have just replaced the motors with commercial off-the-shelf 60Hz versions. Another problem they had after the flooding in NOLA was that the pump stations were flooded too, and the pump motors took a long time to be re-commissioned. There were, of course, no replacements immediately available (or at least, not enough).
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
http://blog.nola.com/times-picayune/2007/05/outage...
crist69,
This brings up another point. It might be simpler and faster to just put in a VFD set for 25Hz output for that motor. It will take a little custom programming of the motor data and frequency/voltage ratios, but all VFDs I am aware of are capable of that. Just be sure to size it for the AMPS, not the HP.
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
I understand that some of the old 25 Hz systems were 2 phase systems. If this is a two phase motor, conversion to 60 Hz may be even more challenging.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
http://www.technology.niagarac.on.ca/people/mcsele...
There were a number of 25 Hz plants and I believe that some of them generated 3 phase 25 Hz.
I remember a paper I read years ago. I think you would have found it interesting.
A plant was using 25 Hz induction furnaces.
The power supplier was phasing out 25 Hz service.
An alternative was sought to the cost of converting the induction furnaces to 60 Hz.
The plant had a number of surplus 25 Hz synchronous motors
It was proposed to use 60 Hz synchronous motors to turn 25 Hz synchronous motors through appropriate ratios to generate 25 Hz to power the 25 Hz furnaces.
Second issue; The plant owned supply of 25 Hz motors did not include any single motor with enough capacity to supply the furnaces.
It was proposed to run two or more sets in parallel to gain the needed capacity.
Next issue; Paralleling. Generally the prime mover supplies torque and the parallel connection locks in the speed and angular position.
However, with synchronous motors driving synchronous generators, the angular position of the rotors becomes important. If the angular position of one rotor lags a few degrees that set will not carry its share of the load. If it lags a few degrees more, it will be driven or "motored".
This problem was solved by fabricating what the engineers called a micrometer coupling. This was a coupling with an adjustable driving link. The sets were started and the synchroscope was observed. The synchroscope would show the electrical angle error between the two sets. The set would be stopped and the relationship between the driving rotor and the driven rotor adjusted with the micrometer coupling. The procedure was repeated until good load sharing was achieved.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
According to his business card, my paternal grandfather was "Superintendent of Phase Change" for Niagara Mohawk in Cohoes, NY. Yeah, it was a frequency change, from 25hz to 60Hz, but they used the word 'phase' instead. Marketing, I guess. His basement accumulated many boxes of perfectly good but useless 25hz clock motors. NiMo exchanged the motors for customers; in those days, clocks came in nice wooden cases, most of which used the same few motor assemblies.
My father, when he was 12 or so, took up photography, and took many photos of the powerplant then under construction adjacent Cohoes Falls; it must have been around 1932.
I went back and tried to sneak a peek while the utility was tearing down most of the powerplant, but it was not long after 9/11, and they were _real_ paranoid about people even just looking through the fences.
</tangent>
Mike Halloran
Pembroke Pines, FL, USA
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Is that the Cohoes station in Mohawk river? If that is so, I can tell you that they are not paranoid any more.
Me and my collegue stayed a couple of days around Schenectady in February 2013. We had been visiting GE and thought that we should visit some other interesting places before we went on to the Museum of Bad art (MOBA) in Boston. When we found that power station, we parked close to it and stared through the gate. Soon enough, one guy asked us what we wanted. We told him that we wanted to see the station. He phoned his boss and then opened the gate. We had a very interesting tour and saw those generators that had been rebuilt for 60 Hz. I took a few pictures of the control panel. It looked like 1940 - 1950 or so. I can send you pictures if you want.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
I should be in the area again next summer.
Maybe I will try standing at the gate and looking friendly.
Mike Halloran
Pembroke Pines, FL, USA
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
It's not accurate to say that Canada used to be 25 Hz. I understand it was just certain areas.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Does any one know if two phase power was used on 25 Hz, 60 Hz or both? The old text books often showed two phase to three phase convesion schemes. Scott, Fortesque and one or two others.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Keith Cress
kcress - http://www.flaminsystems.com
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Further WAG: Flicker didn't become a serious annoyance until tungsten replaced carbon filaments in electric lamps, and electric lamps (vs. e.g. gas lamps) became common.
Mike Halloran
Pembroke Pines, FL, USA
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
But I do not understand "WAG". I googled and found lots of hotties. Does that mean that those motors are running hot?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Mike Halloran
Pembroke Pines, FL, USA
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
SWAG = Scientific Wild Arsed Guess.
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Rewind an induction motor (40 HP) from 25 Hz to 60 Hz
STF