I recently purchased sone 7A-15A Brushless ESC's from AliExpress and they have 3 terminals one end for the motor while the other end has 4 wires. Normally they have a Positive and negative to the batery and then 3 wires to the receiver, or in this case a KP Timer as it is Free Flight. I uploaded the wiring diagram from the site but can't understand it, see below. Here is the advert0000 page. https://www.aliexpress.com/item/1005008113650734.html?spm=a2g0o.order_list.order_list_main.83.6f331802D1FGZ3
What happens if you ignore the unlabeled wire?
UVW are the connections of the motor which as it is brushless functions on AC NOT DC supply. As for the rest red + and black- are the battery connections and the PWM should be the receiver signal the SW is a switch to activate it manually. I have never done such a wiring myself ( as I am a rookie) but have enough knowledge of electronics.....
I agree with Nickhawk. How you use the SW (switch) contact could be one of three ways. 1. Leave it disconnected and use connecting the battery as a way to switch the ESC on. That might work, or might not, I suspect not. 2&3. Connect a switch between the SW terminal and either B+ or B- terminals. With the switch open, that would be same as option 1 so I'd guess the ESC will be disarmed in that condition. With the switch closed, the ESC will arm. Note however that traditionally the standard warning was not to trust a disarmed ESC hat was connected to the battery source, in case it started unexpectedly. Old wives tale? I've certainly seen them glitch often enough to take the risk seriously.
So then the difference between options 2 and 3 is should the SW be switched to battery+ voltage or ground? I don't know. I suspect the safer option is to try grounding the SW terminal while the battery is connected to see if that arms the ESC. If it doesn't, you'll know it needs to be switched to B+. Trying the latter option first would be less safe because if it turns out SW should be grounded and you connect it to B+, you may fry the ESC (at best).
Unless anyone already knows?
Good luck, please let us know.
Cheers
Nigel
Thanks fellas for your suggestions, I have found on the KP Timer where the 3 pin plug of the ESC fits onto the terminals are marked signal, V+ and V-. I was able to read with the help of a Magnifying glass the letters on the ESC which are PWM and SIGINAL AND POSITIVE AND NEGTIVE which confuses me even more. Any thoughts?
Quote from: dputt7 on Mar 01, 2026, 04:53 PMNormally they have a Positive and negative to the batery and then 3 wires to the receiver, or ... a KP Timer...
Hi dputt, from your initial query above,
they (the ESC) will also have 2 or 3 wires to the motor, depending on whether the ESC is made for a motor which is DC or AC (brushed or brushless). In the case of the AliExpress ESC, the receiver/timer positive and negative wires are the same as the battery wires. The picture a little way down the AliExpress page shows B+, PWM, SW, B- pretty clearly, the same as labelled in your picture above.
In your recent post, is it possible the lettering on the ESC says 'PWM Signal' reffering to one location? They can be the same thing, in a way of speaking. Is this ESC the same as in the picture above? Can you post a picture of the offending item? We'll be better able to help with an image.
In your recent post, is it possible the lettering on the ESC says 'PWM Signal' reffering to one location? They can be the same thing, in a way of speaking. Is this ESC the same as in the picture above? Can you post a picture of the offending item? We'll be better able to help with an image.
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Hi Nigel, Yes the photo is the same as the ESC. It does say PWM/Signal so I assume that is what is normally called "Signal". The Diagram also states "the white wire is connected to the positive pole of the power supply", I can't see any connection between the white and the positive but I guess that could be in the circuit board. So with this in mind I connected the white wire to the + terminal on the Timer. A red battery wire to the +. The Blue PWM/SIGNAL to the Signal position on the Timer. Finally I connected the B-to the Neg. terminal on the Timer I also connected the negative batt. wire to the - terminal on the timer.
Now I connected the Timer and connected the battery and NOTHING! Not even any smoke! So It's over to you ;D
Hope this makes Sense Dave
First photo side shown in diagram.
Second photo reverse side
It might be that the white SW wire should be a (or may already be) connected to 0v (- battery) at initial power on then connected to the + battery voltage to arm the pcb. The white wire might in any event be pulled down to 0v by a resistor on the pcb. The purpose would be to prevent immediate motor run occurring on battery connection.
If the white wire is connected to the + battery voltage via a normally open switch it may operate as a press to arm function (needs experimentation to find if this would be an impulse or continuous switch)
Thanks for your interest. I did at one time bridge the battery positive and the white wire but nothing happend.
Yes, but once the pcb is armed you also need the PWM signal value to be sufficient to run the motor i.e. not throttle closed / stop
If the throttle was closed wouldn't you still get the arming beeps as you turn it on. I get nothing.
Thanks for your feedback
Dave
No idea if that pcb would offer audible warnings as has become common for brushless esc devices in general.
Well I'm just about to put all this away and forget it. I actually found some of the same ESC's that I must have bought previously, however they only have 3 wires instead of 4. So I connected it up and gave it a try. NOTHING. I then found a new 10amp ESC and tried that No beeps but after 10 seconds (normal timer delay) the motor made a jittery start but stopped after about 5 seconds with the motor quite warm!
After a search I found my old Turnigy programming card so I'll try to remember how it works and see if I can find a problem.
On the basis that the motor originally did not run at all, then starts hesitantly and gets hot after only 5 seconds run its worth identifying a known good motor by some other unconnected route as a first step.
For all you fellas that have lain awake at night trying to figure
out my problem with the ESCs I have the answer! It came to me the other night while trying to sleep. More of a remembrance than anything, the KP Aero Timer (Brushless) needs to have an ESC with BEC (Battery Eliminator Circuit) and of course those ESCs don't have one. Now all I heed is to find a source of reasonably priced 6amp Brushless ESCs. Thanks to all that tried to help.