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Electronics => Electronics => Topic started by: razarizvi on January 03, 2013, 07:40:11 PM

Title: Advice on how to power the PDX256 geared motor
Post by: razarizvi on January 03, 2013, 07:40:11 PM
Hi All, I need to use a high torque geared motor for a paper shredder. The power will be supplied with a wall adapter (110V). However I am concerned that if the torque gets close to the max 1400 in-lb (1600 kg cm), then the current drawn would be too high.

Can you please give me a suggestion on what kind of power adapter (110 AC to 12 DC) I should use to extract the full range of torque without destroying anything? Will greatly appreciate. Thanks.

http://www.robotmarketplace.com/products/0-PDX256.html (http://www.robotmarketplace.com/products/0-PDX256.html)

PDX256 - 256:1 Gearmotor
Type   Planetary
Stages   4 - 4:1, 4:1, 4:1, 4:1
Gear Material   Steel
No Load Speed   90 rpm
Amps @ nominal:   3.8A Amps
Efficiency:   45.33%
Peak Power:   0.55 hp
Stall current:   148 A
Stall torque:   1400 in-lb
Weight:   19.05 oz (540 grams)
Size:   1.5" (38.1mm) square
Length:   5" (127mm)
Shaft diameter:   1/2" (12.7mm)
Shaft length:   1.5" (38mm)
Shaft Key   0.125in. (3.2mm)
Shaft End Tap   #10-32
Mounting Holes (8)   #10-32


p.s. please let me know if you recommend any better motor with low rpm (less than 30) and high torque (greater than 1000 kgcm) that I can use with an adapter off of 110v.
Title: Re: Advice on how to power the PDX256 geared motor
Post by: waltr on January 03, 2013, 08:47:48 PM
Motor current NOM = 3.8A (which I guess is no load) but 148A at stall (max torque).

You will need a power supply that can source much more than 3.8A so that the motor can do some work (shred paper) but will current limit its output without damage.

You first task is to measure the motors current draw when shredding paper. Then add a little more (20% maybe) to spec the power supply.
Title: Re: Advice on how to power the PDX256 geared motor
Post by: razarizvi on January 04, 2013, 10:26:29 AM
Thanks for the response Waltr. I anticipate situations where the motor will get close to stall torque i.e. 1000 in-lb, so I would assume that the current drawn will be close to 148A, right? I tried to look for a reasonably priced adapter (<$50US) that converts from 110V to 12V and handles 150A current but those run into the hundreds of dollars. Any suggestions on a specific product/adapter that can handle this scenario? Or suggestions on another small motor (max 15cm x 15cm) perhaps that will fetch me 1000 kg/cm torque by directly connecting to the wall socket (110V)?
Title: Re: Advice on how to power the PDX256 geared motor
Post by: waltr on January 04, 2013, 12:53:48 PM
Yep, ~148Amps and hundreds of dollars for the PS.

Maybe look for a motor that runs on 24 or 48V. Remember that V * I = power and it is power that you require and is therefore the constant in that equation.
Title: Re: Advice on how to power the PDX256 geared motor
Post by: jwatte on January 04, 2013, 06:54:45 PM
Quote
a reasonably priced adapter (<$50US) that converts from 110V to 12V and handles 150A

That's not going to happen :-) I've been looking for affordable solutions in the 40A range, and that's still hundreds of dollars. Price goes up with something I'd estimate as the square of the power.
Here's one for $6K: http://www.home.agilent.com/en/pd-839216-pn-6571A/special-order-power-supply-14v-150a?&cc=US&lc=eng (http://www.home.agilent.com/en/pd-839216-pn-6571A/special-order-power-supply-14v-150a?&cc=US&lc=eng)

Maybe a really high-power car battery charger would do it? It's not going to be very clean power, but if it's driving a motor, perhaps that doesn't matter. You can clean it up with a big inductor and a big capacitor. Something that supports 150A current for inductor and similar ripple current for capacitor is going to be expensive, though. This guy claims 200A peak current, but only for a short while: http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_x_5570859-P_x_x?cm_mmc=ACQ-_-Google-_-enhancedRM-_-5570859&ci_src=17588969&ci_sku=5570859&ci_gpa=pla&ci_kw={keyword}&gclid=CI636cCA0LQCFUjZQgodJmMA4A#utm_source=acq&utm_medium=google&utm_campaign=enhancedrm&utm_content=5570859 (http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_x_5570859-P_x_x?cm_mmc=ACQ-_-Google-_-enhancedRM-_-5570859&ci_src=17588969&ci_sku=5570859&ci_gpa=pla&ci_kw={keyword}&gclid=CI636cCA0LQCFUjZQgodJmMA4A#utm_source=acq&utm_medium=google&utm_campaign=enhancedrm&utm_content=5570859)