testing mosfet

[adam333]

Hi,

I am using a Lyen 18 x 4115 MOSFET 84-132V controller on my ebike and I end up losing power on the motor while riding. ( nothing special during the ride, I was on flat surface running at around 10 mph )

Using the controller power, I was able to confirm that the throttle still send the signal to the controller.
Also, using the controller power, I was able co confirm that the hall sensor are still working fine ( going between 0.09V to 5V while turning the wheel )
I have read about testing the mosfet with a voltmeter "diode testing position" without opening the controller and here is the results:
( I disconnected the battery for this test )

Voltmeter probe: (+) (-)
Yellow phase & -Bat = 1.395V
Green phase & -Bat = 1.395V
Blue phase & -Bat = 1.396V
Yellow phase & +Bat = 1.904V
Green phase & +Bat = 1.903V
Blue phase & +Bat = 1.903V
-Bat & Yellow phase = 0.415V
-Bat & Green phase = 0.416V
-Bat & Blue phase = 0.415V
+Bat & Yellow phase = 1.971V
+Bat & Green phase = 1.974V
+Bat & Blue phase = 1.977V
-Bat & +Bat = 0.868V
+Bat & -Bat = 1.778V

I believe I should have saw some "open" result right ?
Do you think I have to replace the mosfet?

Thanks

 

[dnmun]

what is the reading on your diode tester when you hold the probes without touching anything? looks bad.

 

[adam333]

the meter show "3V" ( open circuit )