Hi,
I just wanted a second opinion on wheelchair motor voltage. 24v is nominal for a standard 24v wheelchair motor, however, people have told me you can put up to 36v for about 5 mins and get about 50% more performance. Does anyone see any issues with this besides the obvious one of over heating?
Here is a webpage i found supporting the 36v.
http://www.robotmarketplace.com/products/NPC-B82HT.html
First off, motors are constructed differently. Some will be better at getting rid of heat than others, some will be wound differently and with different gauges and lacquer.
The motor was designed to work reliably at 24V - going 50% over voltage is asking for trouble in some form.
'That aside... Like so many other components, limits are not absolutes and will depend on design parameters and use pattern.
The best way you can find out, if your particular motors will cope resonably well with a higher voltage, is to test it with a temperature sensor bolted to the chassis, preferably at a place near where the windings transfer the heat out.
First run it at the nominal 24V (loaded with a belt brake if possible) for at least 30 minutes, or until the temperature has stabilized (a PC controlled setup would really make it easy). Take notes like "24V, nn°C(or °F)".
Increase the voltage to 26V and wait another 30 mins or until temp. is stable. Note down, increase by 2V and repeat.
As long as the chassis stays below 50°C you should be in the green, but it's hard to put numbers on it, so don't go over say a 20% temperature rise (above the 24V derived temp).
You can then turn things around a bit and stabilize the temp at 24V, then crank it up to 36V and see how long it takes to reach a 20% higher temp.
If you wanna repeat it, allow plenty of time to settle back to the 24V temperature.
When guesstimating, try to err on the conservative side if possible (like 30 minutes may be more than needed at each step up). The temperature rise will take some time to get from the windings to the chassis (hence the 30 minutes to stabilize the temperature) and unless you know the specs of the exact lacquer used on the magnet wire, don't assume it will keep up much above 80°C.