Weapon motor issue

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James Williams
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Weapon motor issue

Post by James Williams » Sat Nov 02, 2019 6:01 pm

Hey all

I'm having an odd issue here. I've been wiring up my new ant today & upon testing my weapon motor doesn't spin. I'm using a Multistar V-Spec 1808 motor with a 12A Afro ESC (both unused). My drive system runs off the same receiver & I have tried switching positions so I know the issue is with either the ESC or motor. When the bot is switched on the green light flashes once on the ESC & there is a beeping noise from the motor so I know the circuit is complete.

Does anybody have any ideas as to what might be happening?

Thanks.

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Kyro
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Re: Weapon motor issue

Post by Kyro » Sat Nov 02, 2019 7:29 pm

some motors require arming when switched on... try 0-100-0 on the throttle and see if it works and/or beeps... whenfirst switching it on, count how many beeps and if they are dots or dashes... it usually beeps codes, for example, twice for 2s,3 times for 3s another double beep for it connecting to transmitter ect
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James Williams
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Re: Weapon motor issue

Post by James Williams » Sun Nov 03, 2019 1:12 pm

Thanks Kyro, however I've just tried 0-100-0 on the throttle & it hasn't changed. The motor beeps once every 5 seconds.

Should also point out that upon powering up the Afro lights briefly flash, first red, then green, before staying off. Does anybody know what this is supposed to mean since there is no mention of this in the manual for them I found online.
Last edited by James Williams on Sun Nov 03, 2019 1:15 pm, edited 1 time in total.

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Kyro
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Re: Weapon motor issue

Post by Kyro » Sun Nov 03, 2019 1:51 pm

that is odd... i use the afro 20a in my spinners and my green light is constant when connected... only flashing when its not connected to a signal iirc. i will check later to confirm this if you would like.

does your afro have the built in bec?
have you disconnected the red servo wire from all but one esc that has a bec as otherwise the bec from each esc will fight eachother.
lipo fully charged?
amp draw of motor below what the esc can output?
motor wired correctly to esc?
Team Rocket Robotics
Esper(4wd flipper)
Mantis (4wd grab 'n' lift)
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MarkR
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Re: Weapon motor issue

Post by MarkR » Sun Nov 03, 2019 3:08 pm

Can you check the PWM signals are getting to the esc? Try testing using an oscilloscope, or otherwise, connect an old servo or something to the same channel, to see if it moves.

I'm also thinking that maybe the wiring can't handle the current and it's just instantly cutting out when it tries to spin up. I don't know how some ESCs make the beeping noises (vibrating the motors somehow) but I guess that probably uses a lot less current than actually trying to spin the motor.

Have you tried running it from a bench supply?

Have you tried measuring the resistance between the phases to check that the brushless motor isn't internally mullah'd ?

Show a picture or diagram of your wiring so others can check it for sanity?

You aren't trying to run the brushless esc off the other esc's BEC output?!
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James Williams
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Re: Weapon motor issue

Post by James Williams » Sun Nov 03, 2019 6:17 pm

OK Having done some research on the motor it seems that their max current draw is 15.8A, which is above what the esc can output. I suspect this might have something to do with it. FYI I've tried using the motor & ESC (which does have a BEC) on multiple channels with fresh lipo & without the drive system installed & always get the same outcome. Unfortunately I don't have an oscilloscope or multimeter to test with.

Attached are some images of the wiring. (Sorry about the mess). Image Image Image

I'll order a 20A ESC & see if that makes any difference. Thanks for your thoughts & ideas guys, appreciate it. If you've got any more I'll be happy to hear it. :)

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Shakey
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Re: Weapon motor issue

Post by Shakey » Sun Nov 03, 2019 9:50 pm

Just a quick one, will it arm if you trim the throttle channel all the way down?
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MarkR
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Re: Weapon motor issue

Post by MarkR » Sun Nov 03, 2019 10:52 pm

It is very unclear exactly how it's wired.

1. Are you powering the rx from the brushed (drive) esc, or the brushless (weapon) ESC?

You should only use one BEC, otherwise the BECs (i.e. regulators) are fighting each other, bad things might happen even if they are configured for the same voltage.

It's ok (but unnecessary) to connect the GND / black wires together, but you shouldn't try to feed the RX from more than one regulator.

2. Do you have a Y-cable on the GND negative wire?

The GND needs to be connected to both ESCs

3. I see you have a switch, is the positive side, connected with a Y-cable to both ESCs?

4. If you really think it might draw 18 amps, then that's not going to work on a tiny little battery pack like the 180 2S packs we usually use; those are not rated for more than about 9 amps (=50C ), and maybe the wiring/ connectors won't take it.

5. Your weapon motor doesn't run, do your drive motors still run? Does the RX light turn on/off when you activate / deactivate the transmitter?
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James Williams
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Re: Weapon motor issue

Post by James Williams » Mon Nov 04, 2019 6:45 pm

Shakey: I've tried the trims, nothing doing I'm afraid.

Mark: Yeah my wiring is a mess as always, I'll try to explain myself:

1) Admittedly the RX is wired up to the BEC's from both the drive & weapon esc's ATM. I will snip the wires on the 20A ESC once it arrives,

2) The negative wires from the ESC's are soldered together, both feeding into the negative on the JST connector for the battery, whilst being wrapped in electrical tape for now to prevent shorting (will heat shrink once I get it working).

3) The positive wires from the ESC's are both soldered onto the switch on the central connection point, with the JST connected to one of the sides.

4) Ah OK, I happen to have a 300mah 70C battery, I imagine I should use that instead?

5) Yes, the drive works fine, as does the receiver, which lights up & off accordingly.

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MarkR
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Re: Weapon motor issue

Post by MarkR » Mon Nov 04, 2019 7:06 pm

Difficult to imagine what might be wrong, but here are some more ideas:

* Perhaps the BEC / regulators are fighting each other? Just try to disconnect one +5v wire
* Maybe the power leads to the brushless ESC are a bit "iffy" and have too much resistance / connected too tenuously to actually run the motor, but the lights flash and it beeps?

Have you tried connecting a servo to the weapon channel, if you have a servo lying around?

I'm not convinced that a bigger battery is necessarily the answer, I'd expect it to at least twitch a bit if it could not draw enough current.
Robots: Betsie - RaspberryPi controlled flipper bot with gyro stablisation - too clever for her own good?
Stacie - tidy flipper; 4wd driven by hair bands

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