Thread: Problem with my bandsaw

Odd.

Originally Posted by petersemple

The switch on the saw is a simple 240V domestic wall switch (DPST).

AFAIK, the average "domestic wall switch" is only SPST and only breaks the live wire... you sure it's a DPST?

Originally Posted by Skew ChiDAMN!!

Odd.



AFAIK, the average "domestic wall switch" is only SPST and only breaks the live wire... you sure it's a DPST?

You are correct, and I can't type

Peter

Peter,
take an air hose and give the motor a good blow out.
As mentioned, switches are single pole and only switch the active conductor. The ELCB monitors earth leakage from the entire circuit, active and neutral, any leakage will register once an unbroken path is established from the ELCB to the leakage point. (There will be a small current flow to earth and no flow from active to neutral, so ELCB trips)
Also blow any dust from the switch on the bandsaw. Another potential leakage site.

AS NCArcher Says, blow out the motor, sounds like the problem is there and if blowing it out doesn't fix it, maybe the capacitor is shot or you've got a broken wire or stuffed windings in the motor.

Originally Posted by NCArcher

Peter,
take an air hose and give the motor a good blow out.
As mentioned, switches are single pole and only switch the active conductor. The ELCB monitors earth leakage from the entire circuit, active and neutral, any leakage will register once an unbroken path is established from the ELCB to the leakage point. (There will be a small current flow to earth and no flow from active to neutral, so ELCB trips)
Also blow any dust from the switch on the bandsaw. Another potential leakage site.

I don't have a compressor. Maybe this might be a good time to ask the wife to let me buy one. Actually, come to think of it, I have a few tyres and a regulator that I use as an air supply for the airbrush. That should do the job OK. I'll give it a go.

Hi Peter,
you say that it first happened when the motor was running. Did you smell anything burning or as if something was overheated in the area of the motor? What can happen is that some insulation in the motor can become slightly broken down so that the leakage current gets up past the trip value of the RCD switch.
As people have pointed out, it can be from the neutral wire to earth as well as from the phase (live) wire to earth.
We had a similar problem in our house with the lights some weeks after I put in a cheap but very stylish light fitting that my wife bought. The RCD breaker would trip despite all the lights being turned off. It was traced down by completely disconnecting (all 3 wires) each light fitting in turn until the RCD breaker stopped tripping.
So try cleaning out the motor and then seeing if it still blows. If it does, then something in the motor is managing to act as a high resistance conductor and your next step is to remove the motor and take it to an electrical service shop for a checkover.
Good luck.
Paul

Measure volts between neutral and earth........