Interesting old Motor
Interesting old Motor
2
roydm (Industrial)
(OP)
Over the weekend I passed through Greenwood BC, there in a park was an ancient Ingersol Rand No 10 compressor hooked to a 3 phase alternator. At first I thought the compressor was a steam engine since it had mechanically activated valves.
The electrical machine was a wound rotor with large solid iron pole pieces with no windings, just a simple copper bus-bar. and seemed to have been built in 1898
I assume the windings were taken off at some stage and the generator converted to a motor.
I can't imagine it was too efficient. Was this common practice?
It had a clutch, I assume it was bought up to speed then engaged like a ball mill.
The electrical machine was a wound rotor with large solid iron pole pieces with no windings, just a simple copper bus-bar. and seemed to have been built in 1898
I assume the windings were taken off at some stage and the generator converted to a motor.
I can't imagine it was too efficient. Was this common practice?
It had a clutch, I assume it was bought up to speed then engaged like a ball mill.





RE: Interesting old Motor
If the pole pieces are solid, the windings would have been DC. This may have been a synchronous motor.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Interesting old Motor
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Interesting old Motor
The spoked spider and built-up rotor indicate that the machine is a low speed type. The bright red section is the winding of the rotor, and behind the dull red of the coupling in the foreground are three sliprings and the rusty remains of the collector. Three rings suggest an AC induction machine rather than a synchronous type with a DC field which would require only two. The radial connections on the spider appear to be at 90° intervals which perhaps suggests there are four connections to the rings but I can only see three sliprings.
Do you have any other images which show the rings more clearly?
RE: Interesting old Motor
Westinghouse Elec. & MFG CO
Pittsburgh PA
Constant Potential Alternate Current Generator
Patented
Stanley Sept 21 1885 NO 349615
Schmid May 29 1888
Westinghouse ETAL Dec 13 1887
Stanley May 29 1888
Shallenberger May 29 18888
Schmid May 29 1888
Schmid July 9 1889 NO 406858
Other Patents Applied For
No 98445 514 Rev.
3 Phase 236 Amperes (could this have been 23.6 Amps) 440 Volts
I'm sure it must have had some field windings at some time but given the poles are solid and it has some shorted out bars next to the rotor you don't think it could have been run like that?
Is it possible Tesla could have had a hand in it
s design?
RE: Interesting old Motor
RE: Interesting old Motor
Must be a "doubly fed"* induction generator then. That's basically a Wound Rotor Induction Motor configured as a variable speed induction generator. It's a very old technology that fell out of favor, but has resurfaced again as a popular choice for Wind Turbines.
*aka "double feed"
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Interesting old Motor
The field is stationary. The solid pole pieces strongly imply DC.
What looks like an amortisseur winding is on the stator. You can see the bolts holding it on. I suspect that it was a retainer for the field windings.
I have run into more than one old alternator with a stationary field and the load current taken off through slip rings.
This may be an alternator repurposed as a synchronous motor, or the "compressor" may actually be a steam engine.
Probably a steam engine. The machine may have difficulty starting as an induction motor with the salient poles. It could start as an induction motor if a squirrel cage winding was fitted to the stator. The device that I suspect is a retainer for the field windings would not function as a squirrel cage winding. The bolts may overheat and there are probably not enough of them to act as a squirrel cage.
I don't like going head to head with two Gurus whom I respect, but I have seen too many alternators with stationary fields.
Here is a link to some pictures of an old Onan, circa 50s or 60s
This has a stationary field and both AC and DC windings on the rotor. The DC winding is used for field current, battery charging and possibly starting. Some similar models have used the DC winding for starting but I don't know about this particular model.
http://oldengine.org/members/diesel/Onan/OnanMenu4...
This is a single voltage 230 Volt machine, hence two slip rings.
I have seen newer Onans with two 115 Volt windings and four slip rings for either parallel or series connection for 115 Volts or 115/230 Volts.
Here's an old Kohler with a stationary field;
Page 27 shows the stationary fields, the slip rings and the commutator.
http://www.oldengine.org/docs/kohler_LP_OM.pdf
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Interesting old Motor
That makes sense. We have become used to alternators with a rotating field and the main output from the stator but originally the field was stationary and the main output was from the rotor. As machine outputs increased in current and voltage the field was moved onto the rotor because of the limitations of the collector gear.
RE: Interesting old Motor
RE: Interesting old Motor
I printed out one of the patents where they claimed a feature was the ability to be able to lift the rotor out in one piece by splitting the frame in half. As an apprentice I was fortunate to work on Ward Leonard and Schrage motors and quite a few other weird DC machines.
I first thought the compressor was a steam engine because it had mechanical rather than pressure operated valves but it turns out the Ingersol Rand model 10 was quite a common machine around the turn of the century.
It was either used for driving underground drills or perhaps blasting air into the copper smelting furnace.
Cheers
Roy
RE: Interesting old Motor
When it was put on display, the compressor may have been more interesting than the original drive machine and so was used instead of the original prime mover.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Interesting old Motor
Would it have been 25Hz and 214rpm?