How much current does a typical wheelchair motor draw?
- Thread starter No0bert
- Start date
How long is a piece of string ? 
http://www.germes-online.com/catalog/41/951/130317/sell_wheelchair_motor.html
They have motors from 200 - 800 W at operating voltages from 24 to 48 volts.
The current drawn will depend on load, ranging from a couple of Amps at no load to over 30A when it is stalled.
http://www.germes-online.com/catalog/41/951/130317/sell_wheelchair_motor.html
They have motors from 200 - 800 W at operating voltages from 24 to 48 volts.
The current drawn will depend on load, ranging from a couple of Amps at no load to over 30A when it is stalled.
I think it is different, I remember a wheelchair manufacterer telling me after around the year 1999, they started making all wheelchair motors that draw 24v a certain amperage, and 12v a certain current. I may be wrong though.
The only spec sheet I found had the price and part number only. Here:
http://www.electricwheelchairparts.com/pridemotorsandgearboxes.htm
They are 660-200-030 and 660-201-031 (1100)
I guess this is what I get for getting them used and cheaply.
The only spec sheet I found had the price and part number only. Here:
http://www.electricwheelchairparts.com/pridemotorsandgearboxes.htm
They are 660-200-030 and 660-201-031 (1100)
I guess this is what I get for getting them used and cheaply.
Andrew Cowan
Senior Member
Most wheelchair motors are rated for 250W continous (so 20A for a 12V motor, or 10A for a 24V motor). However, when climbing over curbs and up steep ramps or slopes, the power output can increase to around 450W (12V=38A. 24V=19A) (for a very brief time).
A 40A controller should be ample for a 12V motor.
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A 40A controller should be ample for a 12V motor.
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How did you figure that out, the relationship between power and current and voltage?
Thanks though.
SilentScreamer
Senior Member
Andrew Cowan
Senior Member
As for knowing the powers, experience. Most wheelchairs use one 250W motor, most mobility vehicles use two 250W motors. The motors can output 450W or so briefly.
However, as Ruzzz shows, the motors could be any power.
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However, as Ruzzz shows, the motors could be any power.
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Never forget Ivy Watts.
Engineers (even 20 year old ones) always remember these things as well as all the basic Ohm's law stuff and algebra and some other stuff.
It's always best to learn. It might seem boring , but otherwise you will always have to get others to do the work for you.
Good luck.
Engineers (even 20 year old ones) always remember these things as well as all the basic Ohm's law stuff and algebra and some other stuff.
It's always best to learn. It might seem boring , but otherwise you will always have to get others to do the work for you.
Good luck.
Rickharris
Senior Member
Don't know about typical but the 250 watt 24 volt motors we use in our electric car generally draw 20 ams at their max torque BUT MANY blow their 70 Amp circuit breaker during races.
westaust55
Moderator
Have a read at this website. With 24V wheelchair motors they went to 60 Amp relays to avoid contact welding.
http://evchallenge.swantafe.wa.edu.au/stealth.asp
24V motor drawing "more than 30 Amps" under heavy load.
Just a few aeons ago when I built an electrical vehicle controller as a Uni project, I used motor car starter solenoids as the battery switching relays to hand the high currents.
Remeber, the watt rating and the max current draw are two different things. Max current draw is stall current, while watts is going to be based on normal or high load (basically, a measure of work done) While the watt rating gives you a good idea of what to expect in power (and current draw) under a normal load, it does not tell you what current rating ESC to use. As an example, the common Mabuchi 550 motor used in many cordless power tools and in RC cars etc. frequently draws only one or two amps, even under some load. However, stall it and it is 80-90 amps.
In one format of RC Model Warship Combat, Fast Gun, they tend to use a lof of 550 motors, and run the ships direct drive (no gears), and often tried to run them (often 3 or more motors at a time) with 15A or 20A Electronic Speed Controllers (ESCs), and complained that the @@$@ piece of !%@ ESCs were blowing, especially in the worst of circumstances (no surprise when you try to draw close to 180A through a 15A rated controller).
Several refused to believe that the motors would draw that kind of amperage, even though the information came direct from the manufacturer (by the way, if the motors are made by Mabuchi, you can fnd the specs on the Mabuchi site, if by Johnson, good luck, if some other manufacturer....?). Them what believed, and checked specs, and sized ESCs appropriate to the max load, have been trouble-free.
It turns out that, in the Big Gun format, we tend more to more efficient motors on gearboxes in the first plac, but also tend to inspect the specifications and size things earlier on (there is more technical stuff in Big Guns ships, so we tend to lean in the technical direction, I guess), and we have had very little problem from the start. Another guy in our club and I happened to independently introduce them in our ships simultaneously (to each other's surprise), and neither of us has blown one due to an overdraw (yet).
I remember being shocked when a 550 motor equipped pump fried the 12ga wiring when it was stalled out (on a 2v, yes two folt, single sla cell SLA)!
Bottom line, you can check the draw with a STOUT ammeter (a little 10A vom need not apply) by applying power and stalling the motor briefly. You will want heavy wire and a stout battery, also. And keep it brief.
Fuses/circuit breakers are also your friend here...
Cheers,
Wreno
In one format of RC Model Warship Combat, Fast Gun, they tend to use a lof of 550 motors, and run the ships direct drive (no gears), and often tried to run them (often 3 or more motors at a time) with 15A or 20A Electronic Speed Controllers (ESCs), and complained that the @@$@ piece of !%@ ESCs were blowing, especially in the worst of circumstances (no surprise when you try to draw close to 180A through a 15A rated controller).
Several refused to believe that the motors would draw that kind of amperage, even though the information came direct from the manufacturer (by the way, if the motors are made by Mabuchi, you can fnd the specs on the Mabuchi site, if by Johnson, good luck, if some other manufacturer....?). Them what believed, and checked specs, and sized ESCs appropriate to the max load, have been trouble-free.
It turns out that, in the Big Gun format, we tend more to more efficient motors on gearboxes in the first plac, but also tend to inspect the specifications and size things earlier on (there is more technical stuff in Big Guns ships, so we tend to lean in the technical direction, I guess), and we have had very little problem from the start. Another guy in our club and I happened to independently introduce them in our ships simultaneously (to each other's surprise), and neither of us has blown one due to an overdraw (yet).
I remember being shocked when a 550 motor equipped pump fried the 12ga wiring when it was stalled out (on a 2v, yes two folt, single sla cell SLA)!
Bottom line, you can check the draw with a STOUT ammeter (a little 10A vom need not apply) by applying power and stalling the motor briefly. You will want heavy wire and a stout battery, also. And keep it brief.
Fuses/circuit breakers are also your friend here...
Cheers,
Wreno
Andrew Cowan
Senior Member
As speed goes down (at a constant voltage), current goes up.
As current goes up, heating goes up.
As heating goes up, efficiency decreases, and damage starts to occur.
Thus when it says 250W, for a happy, long lasting motor, gear it so it draws about 250W at max speed (not including acceleration or climbing).
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As current goes up, heating goes up.
As heating goes up, efficiency decreases, and damage starts to occur.
Thus when it says 250W, for a happy, long lasting motor, gear it so it draws about 250W at max speed (not including acceleration or climbing).
A
westaust55
Moderator
With an AC motor, the motor will draw around 6 or 7 times the nameplate rated current under starting/locked rotor/jammed conditions.
With a stalled/locked rotor DC motor the current will be roughly: Amps = Volts/Resistance.
So, as Rick Harris has pointed out easy to blow a fuse (or trip a breaker) under conditions approaching a stall.
To expand upon Andrews comments,
as the current increases, the heating (copper losses) increases by a square rule:
P (watts of heat) = Amps * Amps * Resistance.
With a stalled/locked rotor DC motor the current will be roughly: Amps = Volts/Resistance.
So, as Rick Harris has pointed out easy to blow a fuse (or trip a breaker) under conditions approaching a stall.
To expand upon Andrews comments,
as the current increases, the heating (copper losses) increases by a square rule:
P (watts of heat) = Amps * Amps * Resistance.
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