Yet another PMDC motor

[Kilted]

Another PMDC motor I'm testing out.  I bought a Amtek 30v tape drive motor off of eBay and it arrived with beat up bearings.  The armature slops back and forth.  It look like the rear bearing retainer was completly broken out.  After I complained the seller admitted that he had used it a windmill.  It looks like the Amtek can not take the lateral thrust loads of a wind rotor.  I made a temp repair by finding a washer that just fit into the rear bearing race, and then a larger washer as retainer that was held in by three self tapping screws in three holes on the rear of the Amtek motor.

Any thoughts on this would be appreciated;

Alomst immediately I see a problem these motor bearings are meant for side loads not lateral loads. So a gear up system with rotor on a jack shaft of even 2:1 would help, with speed range and rotor thrust loading.

eBay store;

http://cgi.ebay.com/ABB-Permanent-Magnet-DC-Servomotor-Type-4414129285_W0QQitemZ110143927922QQihZ001



QQcategoryZ78195QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

eBay auction;

http://cgi.ebay.com/Permanent-Magnet-DC-motor-for-Alt-E-Wind-project-or_W0QQitemZ320169385386QQihZ01



1QQcategoryZ3240QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I bought the $19.99 (new $1,071) so far I can confirm 900 rpm, 13.76v at 6.2 amps charging a battery. I can also confirm at an unknown rpm it blew out a 12v halogen spot lamp I was using for a load.

Basic specs.

Abb 4414129285

Asea Brown Boveri

SERVO MOTOR 24AMP 42VDC 1200RPM

Weight: 10.45 lbs.

This is an Italian made motor and shows it.  First the terminals are fastons which makes it rough to make reliable high current connection, second that cog belt pully.  The shaft is 14.8mm the pully I.D is 12mm with 4mm keyway, pulley is held on by machine screw in end of the shaft with a large shoulder washer. So the armature shaft leaves the motor body at 14.8mm and then steps down to 12mm.  Attaching any thing to the shaft will be a challenge to anyone with out a lathe (me).

I was able to temp. attach a step pulley and v-belt and drive the motor a little bit.  It will be awhile before I can get more spec's I have to find a cog pulley and belt for my drive motor.  Grainger has a large selection but I'm not sure I want to pay their price.  My drive motor has a 5/8" shaft.  My thought here is to build a gear up 2:1 so the rotor can be put on a jack shaft with a thrust bearing.  Then using a cog belt to transfer power. Weather proofing?  The faston connection would have to be soldered and weather proofed.

--  Brandy

[rippersoftware]

You might try a shaft bushing.  These are designed to snug up tight to the shaft as the pulley or bushing face plate is bolted to the bushing.

This guy, Steve, made a mill using an Ametek and the shaft bushing to bolt the hub to the Ametek.  http://www.naturalhealthwizards.com/windpower/

Shaft Bushing - Sure-Grip Bushing by TB Wood

Hope this helps.

RipperSoftware

[bigdan]

You should be able to get new bearings for around $10.00-$15.00. You could take a file to the shaft of the motor with it running and file the big end down to 13mm-1/2 inch. It takes a steady hand but it can be done. Good luck and have fun.

               Bigdan

[Kilted]

Hi,

Thank you for the comments.  On the Ametek never thought of changing the bearings, I just might do that.  Those shaft bushing come in metric sizes with keyways, yet another good suggestion, another thank you.

I have been able to do a little more testing. I manage to get just a couple more readings.  One short circuit reading of 15 amps.  I was most successful in getting some readings while charging.  My rpm counter did not work vary well so rpm's are pretty rough.  Charging 13.4v -  13.7v at 7.6 amps. Rpm was in the range of 900-1100 revs.  What was most notable was how warm it got.  What did notice which will have to be tested again; is as the rpm's went up the voltage dropped off.

I was unable to get a good open circuit rpm reading.  I did have a volt meter on the output and as I reached the fastest speed on the pulley the voltage dropped off, topping out around 50v.

The nameplate calls out 42v @ 24A well only I.L.S. (If Lighting Strikes).  I would call it 7-8 amps continuous.  This is a light duty motor/generator.  I am happy I only paid $37, unit cost, shipping, and tax.  Looks ok for 12v only.  About on par with a Ametek 30.

--  Brandy