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elec motor not responding: motor or esc? (noob question)

just picked up a bellanca decathlon; i've been doing some learner flying and having a ball!

last time out at the field, i smelled a burning smell from the plane. i popped open the battery door and smoke billowed out. i quickly unplugged the battery and then removed the wing.

the green covering over the battery looks to have melted a bit in a couple spots. nothing looks unusual inside the plane. the ESC looks fine. i cant really see the motor.

when i reconnect the battery to the plane, the servos still respond to stick inputs...but the motor doesnt respond.

before i start tearing into the plane, anyone know how i can tell whether the problem is the motor itself or the ESC?

TIA walter franklin, michigan

Reply to
walter
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You need a voltmeter for a couple things.

The Battery may have one or more bad cells, placing it's voltage too low for the ESC (probably a BEC) to supply the motor, but high enough to run the receiver and servos.

Measure the voltage on the leads to the motor. Is there anything, and does it respond to the transmitter?

Measure the battery voltage. Is it correct for the number of cells?

Don

Reply to
Don Bowey

Reply to
walter

yah...battery puts out plenty of volts. a couple over the rated value.

motor works fine...spins right up when connected directly to batt.

BEC is dead. not a single volt, joule, amp, watt, whatever comes out.

are BECs pretty much swappable between makes? i have no idea if i have to get some proprietary unit. the connector looks like a std plug into the receiver, same as found on the servos.

walter.

Reply to
walter

On Sat, 30 Jun 2007 14:00:13 -0700, walter wrote: (top posting fixed)

I think you're confused about terminology. "ESC" stands for "electronic speed control", which is the part that doesn't work. "BEC" stands for "battery eliminator circuit", which is the part that _does_ work in this case.

You need a new ESC. As the signal from a receiver to a servo is pretty standard these days, they're interchangeable. You need to make sure that you get one that will carry the current your motor needs and will stand up to your battery's voltage -- beyond that, you have a world of choices.

Reply to
Tim Wescott

AFAIK when both functions are contained in a single package, it is still called a BEC. That is the case with at least a couple of mine.

Reply to
Don Bowey

Likely both, sadly...

Reply to
The Natural Philosopher

You are lucky then. Yup Any ESC with enough current rating will work.

Reply to
The Natural Philosopher

No, its called an ESC (with a BEC)

Reply to
The Natural Philosopher

it's a combo ESC/BEC.

the ESC side is fried. the BEC side still works. not that it buys me anything.

i pulled off the heat-sink and one of the SMDs looks like a mini mt. vesuvius.

w
Reply to
walter

Probably a power FET. Not that hard to replace if you can be arsed.

Reply to
The Natural Philosopher

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