Hello to all experts. My first post here.
Hope it's OK to ask this rather general question about BLDC motor in this forum topic.
I have a 3-phase BLDC motor (as part of a cordless screwdriver) with 3 hall sensors (type J55 eD) inside.
SOMETIMES, when pressing the main switch, the motor does not start, and the only way to get it started is to disconnect the battery pack and reconnect it again. Then the motor works normally again until the next failure which could be in the next hour or the next day.
Any idea why this is happening? Can someone give me a hint as where to look for the reason ? Is it the motor hall sensor, the drive electronics … ?
Thank you, in advance.
SAFAI
Who knows, this involves putting it on the bench, taking it apart, getting the test equipment out
and troubleshooting it... Suspect everything, eliminate one by one till you find a problem, fix it,
and repeat until its working fine, or you have to give up.
Given the symptoms is suggests some sort of lock-up in the drive electronics, but that might be
a symptom of it detecting erroneous sensor input too. Its best not to make assumptions though,
that usually leads to blind alleys - collect data.
Usually the fastest way to make progress for something like this is to swap parts with a known
good unit, thus narrowing down which unit is involved.
Hi,
Is the battery, the battery that came with the screwdriver.
It sounds like a BMS (Battery Management System) is detecting low battery and disconnecting the batteries to protect them.
How old is the screwdriver?
Have you got a DMM to monitor the battery volts when you operate the screwdriver?
Tom...
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