Speed controller and motor wattage

Electric Motors and Controllers
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Ramsart
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Speed controller and motor wattage

Post by Ramsart » Dec 04, 2017 11:50 pm

Hi,

Can anyone help my question i have 500 watt 36 volt motor can i use a 36 volt 350 watts speed controller

What are the disadvantage and will the speed controller have a shorter life span?
Is it better to use 500 watts controller instead?

Additional question whats the difference between sine wave and square wave which is better to use.

Manny
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Location: The Netherlands

Re: Speed controller and motor wattage

Post by Manny » Dec 12, 2017 2:43 am

the 500 watt of the motor is the max, so driving it with a 350 watt controller is on problem.
the sine controller make less noise and can be smoother.

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macribs
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Re: Speed controller and motor wattage

Post by macribs » Dec 18, 2017 4:27 pm

Motor ratings you can thing of as understated, most motors will handle way more and be happy doing so. People here run 14-15kw into a 3 kw motor. And have for years.

But to get motor to output more then rated power you need a bigger controller. If you use 350 watt controller, you will underpower your motor. Bigger is better for controller.

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geoff57
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Re: Speed controller and motor wattage

Post by geoff57 » Dec 31, 2017 3:10 am

Hi
To many degrees you can forget about the wattage rating of the motor a lot of my motors are only rated at 250w but I can pull 1.5kw out of them.
As for controllers there is a general rule of thumb whatever the wattage rating of the controller you can pull twice that, so a 500w controller will draw a max of 1kw when under maximum load, a side note if there are bridges or hills where you are you will need at least 500w to get over without peddling 750w would be better.
Geoff

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DrkAngel
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Re: Speed controller and motor wattage

Post by DrkAngel » Dec 31, 2017 10:40 am

Ramsart wrote:
Dec 04, 2017 11:50 pm
Hi,
Can anyone help my question i have 500 watt 36 volt motor can i use a 36 volt 350 watts speed controller
350w controller should work with no "problems".
Performance on acceleration and hills will suffer!
But, top speed on level travel should be just as good.
Economy should improve, partly due to more efficient amp throughput, mostly due to encouraged pedal assist getting up to speed and on hills.
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casainho
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Re: Speed controller and motor wattage

Post by casainho » Jan 03, 2018 10:13 pm

Ramsart wrote:
Dec 04, 2017 11:50 pm
Additional question whats the difference between sine wave and square wave which is better to use.
Go with a sine wave, as is more silent and efficient.

I suggest you to use this controllers that are sinewave: https://opensourceebikefirmware.bitbucket.io/
Developer of the Flexible OpenSource firmware for EBike motor controllers: https://opensourceebikefirmware.bitbucket.io/

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