Capacitors on Speed controls
05-02-2010, 05:03 AM
#1
Capacitors on Speed controls
Hi Guys,
I want to know what a capictor does fon a speedy control. I am running a QC3 Speedy forbrushed 540 motor.
I currnetky dont have a capacitor, and speedies i use to have always had a capictors, but this one doesn't, i am starting to wonder if i need to have one.
Some people say it gives yo ua boost.
What size capcitor should i use and how do you attach it??
Regards
Brad
I want to know what a capictor does fon a speedy control. I am running a QC3 Speedy forbrushed 540 motor.
I currnetky dont have a capacitor, and speedies i use to have always had a capictors, but this one doesn't, i am starting to wonder if i need to have one.
Some people say it gives yo ua boost.
What size capcitor should i use and how do you attach it??
Regards
Brad
05-02-2010, 08:01 AM
#3
Tech Initiate
Capacitor stabilize the voltage to your esc...lower esc temp, better punch ..
05-02-2010, 08:24 AM
#4
how much capacitence do we need exactly then?
05-02-2010, 08:36 AM
#5
05-02-2010, 05:04 PM
#6
Tech Adept
the capacitor smoothes the large'ish voltage spikes caused by the motor and the ESC transistors switching at high speed. It doesn't give you any boost, the amount of energy stored in the cap is miniscule.
05-02-2010, 06:37 PM
#7
Tech Regular
i would like to reinforce what gameover said. the capacitor is to smooth the voltage spikes created by the ESC since it is PWM (pulse width modulation) and thereby keeping the speed control cooler. to see any noticible difference in punch you would need a capacitor almost as big as your battery. older speed control with big cases had the capacitor(s) inside them but most new high-power speed controls have them external.
05-02-2010, 08:21 PM
#8
Caps also serve the purpose of absorbing spikes when braking. When the ESC applies brakes the motor is turned into a generator, and can produce a large voltage spike, which can cause issues in the ESC and batteries if nothing is there to absorb it.
Make sure to use low ESR (equivalent series resistance) caps and solder them as close as possible to the ESC board (also to keep to overall resistance as low as possible). The caps should be rated to 105C, and it is better to use multiple caps instead of one large cap (e.g. three 500uF caps in parallel instead of a single 1500uF cap) because the multiples allow better heat dissipation.
Make sure to use low ESR (equivalent series resistance) caps and solder them as close as possible to the ESC board (also to keep to overall resistance as low as possible). The caps should be rated to 105C, and it is better to use multiple caps instead of one large cap (e.g. three 500uF caps in parallel instead of a single 1500uF cap) because the multiples allow better heat dissipation.
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