Author Topic: Check on suitability of motor  (Read 3124 times)

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(unknown)

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Check on suitability of motor
« on: March 09, 2010, 11:50:35 AM »
I have been wanting to put together a small scale hydro generator but have not found a suitable motor until maybe now.  In cleaning the office I was about to toss an old blueprint machine (Bruning PD101) and noticed that the drive motor was listed as a DC motor.  Here are the specs from the motor


RAE Corporation

90V DC 38rpm

0.47 amps 50inLbs Torque

model 241839 date J88


I marked the first gear off the gearbox and noted using the variable speed setting of the machine the rpm varies from 4 to 50rpm.  If it is not suitable I will be donating it in whole so I haven't tried to take it apart yet to see the resistance by hand to spin.


I know I will need to calculate flow and head eventualy but until it's not frozen that will have to wait.  Just looking to charge a small 12V system for the cottage used on the weekends.


Thanks.

« Last Edit: March 09, 2010, 11:50:35 AM by (unknown) »

tanner0441

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Re: Check on suitability of motor
« Reply #1 on: March 09, 2010, 12:08:11 PM »
Hi


2.3 RPM per volt, It's only going to be about half an amp but it sounds a wonderfull thing to play with, and you could be in the rare situation you could gear down.. That is of course assuming it is a permanent magnet motor not a wound unit.


I hope someone on here knows the motor and can give you real help with it.


Brian

« Last Edit: March 09, 2010, 12:08:11 PM by tanner0441 »

TomW

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Re: Check on suitability of motor
« Reply #2 on: March 09, 2010, 12:33:11 PM »
A half an amp 24/7 might provide sufficient battery charging to use sparingly on weekends for lighting done right.


bit over 80 AH a week could keep a few LED lights burning on weekends it seems plus some power for a radio or something,


Make a nice learner project I would think if nothing else. Depends on the motor being permanent magnet, however.


Tom

« Last Edit: March 09, 2010, 12:33:11 PM by TomW »

tbjeepguy

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Re: Check on suitability of motor
« Reply #3 on: March 09, 2010, 12:45:07 PM »
Thanks for the quick responces.


I did manage to remove the gear off the drive and tried but am unable to spin at all by hand. not sure if that is just the ratio in the gearbox reducing it too much.  I will bring in a battery drill to work tomorrow to see if it can spin the motor at the gearbox end.  What methods are there to confirm if it is permanent magnet.  I was able to check and it does have brushes.


Even at 0.5amp per hour is more than 0 so would be enough to get working on the rest and upgrade it later if it is found to not be sufficent.

« Last Edit: March 09, 2010, 12:45:07 PM by tbjeepguy »

tanner0441

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Re: Check on suitability of motor
« Reply #4 on: March 09, 2010, 02:40:31 PM »
Hi


If it derives its shaft speed from a gearbox it may not be the dream item it first seemed. you need to know the speed the motor turn at before any gearboxes.


A quick check if it is a permanent magnet motor is see if a screw driver sticks to the casing.  The other way is to pull off one of the end caps and look inside.


Brian

« Last Edit: March 09, 2010, 02:40:31 PM by tanner0441 »

tbjeepguy

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Re: Check on suitability of motor
« Reply #5 on: March 10, 2010, 01:08:11 PM »
I managed to open up the motor and confirmed it is a PM motor, although they appear to be of the ceramic type. In the process of reassembly i think one of the gears in the gearbox became misaligned and now that is not functional without a new shaft on one of the gears so I would likely have to run off the main shaft speed. Im assuming with the number of gears in the gearbox it turns signifigantly faster than the 38rpm as listed on the motor plate.  Looking up at other RAE motors seems to be that most spin at 1700-2000rpm so with a broken gearbox thats what i have to work with. Its hard to know the resistance of the main motor shaft as i wil have to break the gearbox housing to reattach it as it is part of the main motor casing prior to testing.

« Last Edit: March 10, 2010, 01:08:11 PM by tbjeepguy »