P2 Motor Failure

[r1fmc]

Hi,

I'm new to this forum and would really appreciate some advice.

My P2 is only a few months old and has done very little flying. After fitting an ImmersionRC transmitter one of the motors wouldn't spin, it just 'judders'. I don't think fitting the transmitter was the cause, perhaps just coincidence.

I fitted a new motor, but it was just the same. I then fitted a new ESC, but again, it was the same. I've tried the new ESC with both the old and the new motor, no difference.

I'm stuck now, I don't know what else could be causing the problem.

If anyone else has experienced this problem and found the resolution,I would be pleased to hear from you.

Thanks in advance.

John

 

[IflyinWY]

Sounds like you have too long of a screw.

If the screw can contact the windings of the motor, that's it. The motor is toast.
Do you have Prop Guards? If so, you have to be very careful not to use the long screws without the guards. The difference in length is, well, I don't know, but very little.

Where are you flying John?

Welcome to the forum, it's a pretty cool place to find out what's up there.

http://www.wynotweb.com/PropGuards.html

 

[Hughie]

Sounds like an ESC has gone. If you have a secondary cause like long screws in the motor that will instantly blow the ESC again.

 

[r1fmc]

Sounds like you have too long of a screw.

If the screw can contact the windings of the motor, that's it. The motor is toast.
Do you have Prop Guards? If so, you have to be very careful not to use the long screws without the guards. The difference in length is, well, I don't know, but very little.

Where are you flying John?

Welcome to the forum, it's a pretty cool place to find out what's up there.

http://www.wynotweb.com/PropGuards.html

Hi, thanks for getting back to me.

Thanks for your advice, but the screws are not causing the problem, the failed motor has the same length screws as the other three motors, all of which work okay.

I did use prop guards when I first bought the P2, but swapped back to the shorter screws when flying without the guards.

It's not had a great deal of flying time, as I've had quite a few problems with it since I bought it just before Christmas, when I do fly it's around my house & garden, or used to until this motor/ESC issue!

Cheers,

John

 

[r1fmc]

Sounds like an ESC has gone. If you have a secondary cause like long screws in the motor that will instantly blow the ESC again.

Hi, thanks for your advice.

It's a new ESC fitted out of the box with a new motor, so I don't see how it can be an ESC problem?

Cheers,

John

 

[Hughie]

Can you send a picture of it, as it is fitted ?

 

[TeamYankee]

Does the faulty motor turn with the same amount of resistance as the working motors? (power off of course!)

 

[r1fmc]

Can you send a picture of it, as it is fitted ?

Here you go, ignore the connectors, they're just a temporary fix until I can get to the bottom of the problem.

Thanks again....

 

[r1fmc]

Does the faulty motor turn with the same amount of resistance as the working motors? (power off of course!)

The resistance feels the same as the other three motors.

Thanks...

John

 

[IflyinWY]

It looks like your connectors offer an excellent testing point. Have you checked the voltage going to the motor while it should be running?

 

[r1fmc]

It looks like your connectors offer an excellent testing point. Have you checked the voltage going to the motor while it should be running?

No, I haven't, could you advise the best way to do that please?

Thanks....

 

[IflyinWY]

Yep, here's your advice.

Find someone smarter than me to tell you how to do it. It's still an idea I haven't tried.
I just sent a message to CityZen asking him to look at your thread.

 

[CityZen]

I just had an issue with a motor that wouldn't spin, but would only judder. It was a defective motor. I was able to see a broken winding on one of the coils. I also measured the resistance between the 3 wires. The resistance between one pair was double that of the others.

If I were you, I'd also use a multimeter and measure the resistance across all 3 pairs on the motors. They should all be about the same. If one reading is higher, that motor is defective.

 

[N017RW]

The only way for us 'mortals' with just DMMs to bench test an ESC is to swap with a known good one.

Motors can be tested by reading the resistance of each of the three coils. They should be close to each other and similar to other motors of the exact same type.

 

[r1fmc]

I've just been running all the motors for less than a minute to test the voltage going through the faulty motor. When I stopped the motors I noticed that the faulty motor was quite warm in comparison to the other three, suggesting the problem may lie with the motor and not the ESC.

Despite the fact that I had initially tried the new motor with the new ESC and I had experienced the same problem, I decided to swap the motors again and guess what......and it ran perfectly!

I don't know why it didn't run properly the first time it was fitted, it's really bizarre!

Thanks to you all who took the time to try to help, it's very much appreciated.

Hopefully I can get back to some flying now, but rest assured, I'll visit the forum regularly from now on for more words of wisdom.

Thanks again.

Cheers,

John

 

[Hughie]

The picture looks fine too me. I see that you have now sorted your problem. I would keep an eye on it in case it is an intermittent fault.

I dont think there are any simple voltage tests you can do to the ESC. It has a PWM input and drives the motor using 3 phase, energising a pair of the windings at any one time. The best electrical test you can do of the motor is to test continuity as follows, with it removed from the ESC:

Measure the resistance of each wire with each of the other two. In each case this should show as very low resitance, a few ohms.

Measure the resistance of each wire with the case of the motor. In each case this should show open circuit.

 

[r1fmc]

Although I ran the faulty motor for less than a minute, could the resistance on the motor have damaged the ESC in any way?

I hope it's not an intermittent fault, I wouldn't like it to manifest itself whilst airborne with all my kit on board!

Cheers...

 

[r1fmc]

After making permanent connections to the ESC and putting the P2 back together, on start up exactly the same problem has reappeared!!

I think I'm going to have to replace the ESC & motor.....again. I didn't anticipate having this much hassle & extra cost with a new P2 that's hardly flown.

 

[Hughie]

Did you try swapping the ESC signal cable with another arm?

 

[r1fmc]

Did you try swapping the ESC signal cable with another arm?

No, I'm not sure how to do that?