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Author Topic: The need for fuses  (Read 6045 times)

malcolmfrary

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Re: The need for fuses
« Reply #25 on: January 18, 2008, 11:44:51 am »

In the days of resistance controllers, a close match was essential.  This is no longer the case with PWM ESCs.  Generally, what will handle a lot, will handle a little.  There will be some exceptions such as ESCs designed specifically for high performance where accurate low speed control is not a requirement, and a certain amount of coarseness can creep in.
A PWM ESC, by switching full-on and full-off, varies the proportion of full power offered to the motor, either by having a constant pulse rate and varying the length of time the pulse is "on" or having a set pulse length and varying the rate at which the pulses are generated.  The motor is always offered the full power when the controller is "on", but if the controller is only "on" for 25% of the time, the motor gets 25% power, with speed to match.  Provided the motor can handle the voltage, and the ESC can handle the current and stand up to the voltage, the same level of control is available over a wide range of motor and voltage with the same ESC.
Hope that makes sense.
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DickyD

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Re: The need for fuses
« Reply #26 on: January 18, 2008, 12:06:37 pm »

It's a completely different language isn't it ? :-\
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explorer750

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Re: The need for fuses
« Reply #27 on: January 18, 2008, 06:09:15 pm »

Just some more details on the speed controller, its a Electronize Type FR30 HX


Smooth P.W.M. forward and reverse speed control.
Selectable operating mode.
Low frequency mode: 100Hz
Variable frequency mode: 10 to 1000Hz
High frequency mode: 2000Hz
Low loss Power MOSFET current switching. (Only 2.7 milli-Ohms)
Low loss heavy duty cables. (0.25mm2)
High current automotive relays designed specifically for high power motor control.
Precision pre-set neutral.
Adjustable speed range to match throttle stick travel or scale speed.
6 to 24 volt motor battery operation. (5.5 volt min.)
30 amp. continuous load rating in either direction.
90 amp. short term stall rating. (continuous MOSFET rating)*
540 amp. peak rating.
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malcolmfrary

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Re: The need for fuses
« Reply #28 on: January 19, 2008, 12:31:12 pm »

Quote
It's a completely different language isn't it ?

When you look at the innards, the phrase "I couldn't do that" springs to mind. 
The modern controllers (i.e. electronic) are a LOT easier to set up and much better behaved than the stuff that went before.  What downsides there are are easily worked round, usually by reading the instructions.  Official fusing recommendations would be good, though.  At the moment we are doing the practical thing of discussing the whys and wherefores, and hopefully a useful formula will appear sooner or later that will both work and be easy to follow for a beginner, especially one without an electrical background.
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explorer750

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Re: The need for fuses
« Reply #29 on: January 24, 2008, 07:38:13 pm »

I'll second that.
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