Forget about that claw I posted about earlier. It looks cool but I couldn’t find a multimeter to work with it. The first one I purchased for $10 that didn’t have a “range” indicated in the claw’s specs. as you know. I went to Discount Builders with the claw’s booklet. It says:

The 72-555 is designed to be used with digital multimeters that have an ACV input impedance >= 1.0 Megaohm and a 2 VAC(or more sensitive range).

I don’t know about the impedance. It’s like the AC version of “resistance in a DC circuit”. However I don’t know much at all about AC. They are worlds apart. AC is the current that is a sinosoidal wave where the current is flowing one direction on the positive peak and the other way on a negative peak, all within milliseconds. DC is more mellow and fits the water pipe analogies much more evenly.

An $80 multimeter at the store had a 2 VAC (Volts AC) setting though. I’m measuring current (amps) but what comes out of the claw is volts in a ratio to the current it hears rumbling in the wires. Great!

Not great because 2 VAC is the minimum sensitivity for the claw and the maximum sensitivity for the multimeter. The washing machine runs 9.8 amps. For 9.8 amps I need to read things in a 100mV range. That one twentieth of 2 V. And the purchase is nonrefundable.

I had a plain old $80 clamp ammeter sent to me yesterday morning via UPS. Which did the trick. This is a staged set up in the photo. I had set up the cord so I would only be reading one of the wires, positive or negative.

So here is what the washing machine is all about. When it is not running it varies between .00 and .01 amps. It was set for the 14 minute cycle on Cotton Sturdy, with a high water level and Cold/cold water temperature.

1. 1st cycle (fill basin) – .05 to .06 amps
2. 2nd cycle (wash) – first a spike up to 11 amps then 9.66 to 9.16 (manufacturer says 9.8 amp, so looks good)
3. 3rd cycle (drain/spin) – a drop to .02 amps and then back to the varying 9.x range though generally slightly lower than wash.
4. 4th cycle (spin) – a drop to .02 amps then back to 9.x
5. 5th cycle (refill) – a drop to .02 amps then up to .06
6. 6th cycle (rinse = fill and drain simultaneous) – a spike to 11 amps then 9.x
7. 7th cycle (drain only) – a spike to 16 amps(!) then 9.x
8. 8th cycle (spin) – a spike to 11 then to low 9.x and even 8.9
9. 9th cycle (reverse spin?) – a spike to 11 and then 9.x
10. 10th cycle (finish) – a drop to 2.x amps then finally to 0.00 amps

What seems strange looking at this right now is that sometimes when it is going from wash into drain it drops to 0.02, then later seemingly making the same transition (from rinse to spin) it spikes instead of drops.
Also what was interesting was I tried looking at the max amps using a special setting and for one of the spikes I got a reading of 32 amps! I think it’s an indication of the size of the wave. Chances are what the manufacturer and the measurement instrument are referring to when expressing the current involved is the average value of the half cycle. Average value of voltage “peak to peak”, from the positive peak to the negative, would always be zero. So an average of the absolute value of half a cycle what is known as voltage “root mean square” ( 0.707 times the peak voltage) will give you a meaningful number that describes everything. Voltage root mean square is the equivalent to DC voltage in producing heat in a resistor.

UPDATE: I’m learning about AC, and impedance, so it’s funny to look back on this.