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Post by Just checking on Mar 1, 2020 22:15:17 GMT
Just checking as I have seen this in other questions for 2020 are we allows to do 48 Volts at 40 amps? By this I mean can we go up to the thermal cutout or is it that we need to run the motor at under 1000 Watts?
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Canterbury Coordinator
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Post by Canterbury Coordinator on Mar 3, 2020 21:00:09 GMT
From our head scrutineer:
We require motors to not exceed 1000W, the cutout is designed to ensure this.
In practice other design factors such as tyres, alignment, cable and controllers will have a greater effect on performance than say a 975W motor vs a 1025W motor.
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Post by josh573a on Apr 17, 2020 3:54:18 GMT
If we were to spike above, does the bimetallic strip thing cut all power and need resetting, or does it limit it back down to 1000w?
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Post by deni on Apr 20, 2020 7:14:14 GMT
Hi Josh, From our scrutineer and other techies:
If they go above the capacity of the cutout it will indeed cut out! It will not simply limit them to 1kW source power. When the thermal overload trips there is a 28s reset time. This means they will have to wait until the cutout cools before they can reset it and drive again. Teams need to drive comfortably under the limit in competition or have a way of seeing (Current meter on dash) how close they are to the trip threshold.
It's probable other design and construction features will affect success more than motor power.
That is, it's false to think that a very big motor will be beneficial. Big motors have poor efficiency at normal running loads. Motor efficiency curves should be matched to running loads for each event. A real keen team could fit different motors for each event.
Another real keen team could measure the current/time characteristic of their overload and then make an instrument that displays how close to the limit the system is at and roll back the power to prevent shut-off – or warn the driver to do so.
(Overloads click off. The power is not rolled back)
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