methods for testing the coil in an a/c compressor clutch

**thechuckster** · 13-08-2011, 01:02 AM

any suggestions for how to test (electrically) the state of the coil in an A/c compressor clutch?

The unit i scabbed for my 3SGE motor seems to be pretty poor at clamping the hub up tight. Admittedly the friction material on the rotor has been mostly worn away, but the clutch in my old MA61 & RA40 compressor pulled the hub together really tightly (and loudly) compared to this.

fwiw: compressor is out a mid 90's 5SFE-powered camry.

**CrUZida** · 13-08-2011, 09:08 AM

All the 'newer' AC's I've played with a pretty quiet.
Talking circa 7MGTE/1UZFE early 90's.

Put 12V on the clutch and there is little click and the pulley moves back about 2mm.

Definitely no big thump. Never had an issue with it slipping either.

**thechuckster** · 13-08-2011, 01:10 PM

So on the later models the outer pulley with the ribbed belt section not the inner bit bolted to the compressor shaft?

i powered this one up via the battery charger and could overcome the clutch. will try a proper power supply.

ta, charles

**CrUZida** · 13-08-2011, 01:34 PM

Sorry, your right, the pulley doesn't move back, but the bit that bolts to the main shaft does. (if that makes sense)

**thechuckster** · 13-08-2011, 04:40 PM

yup, makes sense.

**thechuckster** · 13-08-2011, 07:08 PM

well that was annoying. Used a stuffed drycell 12v battery from one of my brother's work data loggers and the a/c/ clutch clamps quite strong.

**CrUZida** · 13-08-2011, 07:32 PM

Interesting.
Maybe the battery charger needs a decent load to produce decent current?

AC Clutch would be tiny amount of load.

**thechuckster** · 13-08-2011, 07:50 PM

has got me thinking - charger came from supacheap many eons ago so i expect it to have very simple electronics that just controlled current output based on impedance of attached battery (which would indicate charge state) and peg it if it hit a defined maximum current draw. Maybe it shut down thinking that the high impedance of the coil indicated a fully charged battery.

Anyway, now the fun part of finding someone in Oz who will sell me a bearing and also a seal kit for the compressor (heaps on US A/c workshop website that will retail service parts but cannot find a here in oz, yet anyway).