Multi-meter question

[1948man]

When I measure the resistance of any 2 of the 3 stator wires, My needle swings over to the right of zero. I guess this indicates no resistance while the stator papers look for between .5 and 2 ohms. The only ohm scale I have is X1K or in other words a reading of 1 is actually 1000 ohms I guess. This is the meter (too cheapo?) I have. http://www.byramlabs.com/product_inf...%20Multimeters
I did adjust the needle to zero before using. Does this indicate my stator is bad? With this scale it would be pretty hard to measure .5 to 2 ohms, or are those supposed to be K/ohms.

[cwdusmc]

Meter Question

You are correct, your meter will not effectively read anything below 1000 ohms (1K). Therefore, you will not be able to tell whether the stator windings are shorted out or not, due to the low resistance of the windings (since they are just really long wires). All you can tell would be whether or not any of the leads/windings have a break in them. When you say the "stator papers look for between .5 and 2 ohms" I assume you are referencing a service manual?
Either need a meter with more resistance scales or perform a running voltage check of the coil outputs (depending on the bike).

Good Luck,
Craig

[Steve]

There is nothing wrong with that meter, but the user, ...

No, really, if you zeroed the meter by crossing the leads, there is NO WAY that the meter will swing past zero when you test a wire. There should be no problem reading .5 to 2 ohms, either, that's about 1/4 of the swing of the needle. The zero that you should be setting to is that one in the upper right corner. The scale then goes to the left, should be no problem seeing something between .5 and 2 ohms. And no, that's not K ohms. 1K ohms would barely tickle the meter from where it is in the picture.

Also keep in mind that all three stator wires should be disconnected from anything else while you are testing them to ensure that you are testing ONLY the stator.

I did not see the zeroing adjustment. Is there a knob or something on the side? The procedure is normally to plug your test leads into their holes in the meter, touch the two leads together. The meter should swing full-scale to the zero in the upper right corner. Move your adjuster so the needle reads exactly zero, then apply your test leads to the stator wires to read their resistance.

.

[Steve]

You are correct, your meter will not effectively read anything below 1000 ohms (1K). Therefore, you will not be able to tell whether the stator windings are shorted out or not, due to the low resistance of the windings (since they are just really long wires).

That meter will do JUST FINE for testing your stator.

You don't need anything over 1K, you need exactly what you have, the .5 to 2 ohms at the right end of that outer scale.

.

[cwdusmc]

You are partially right, I misspoke by a factor of 10! The meter will read effectively down to about 100 ohms since the first "tick mark" on the right side of the meter is 200 ohms. The "1" on the scale is 1K ohms. According to the manual the ohm scale is: Resistance: 0-1Meg (5K W mid scale). Therefore, the 1 is 1K and the 1K on the left edge is 1K times 1K or 1 meg.
The meter is not sensitive enough to try and read anything below about 100 ohms with any accuracy.

Sorry for the confusion.
Craig

[1948man]

The yellow screw on the face of the meter just to the right of the word Sperry is used to zero out the meter. The directions say to set the needle over the three zeroes at the left of the 3 scales. I'll read some more or try what you suggested. If I get a reading of 1, wouldn't that actually be 1K ohms? Thanks Jim M

[1948man]

My wife is making me watch a dvd of Avatar now, but I will be back.

[cwdusmc]

Initial setting on the meter for "zero" would be on the left side. However, when you check for zero ohms, by holding the two test leads together, you are looking for zero on the right side, per the manual instructions:

6) PLACE THE SELECTOR SWITCH ON THE SP-5A into the “X1K” position, hold the tips of the Red and black test leads together and adjust the “OHMS adjust knob” until the meter movement pointer reads “0” on the “OHMS” scale located at the extreme right side of the scale plate.

The "OHMS adjust knob" i believe, should be the "thumb wheel" on the left side of the meter. You are correct, a reading of "1" on the top scale would be 1000 ohms or 1K.

Craig

[Guy]

I wouldn't trust a cheap analogue meter to measure a low resistance like a stator winding.
Simplest thing to do is disconnect the block from the stator and measure the running AC voltage across all three pairs as already suggested. At 3,000 RPM ya should have 70/80 VAC across each pair. If any or all of them are significantly below this you have a bad stator.

[1948man]

I'll get around to the voltage test but first the meter. Yes, there is an ohms adjust knob on the side and I have done that adjustment now. It was described in the manual in the section about testing the internal battery of the unit. I'm not sure what the first needle adjustment accomplished, but it's all good now and I will retest the stator leg restistances when I get free to do so.

[Guy]

cwdusmc is quite right;
the first increment on that meter reading from right to left is 200 ohms.
It would useless for measuring anything below that value with any accuracy.
Get a decent meter or do the running voltage check.

[1948man]

I'm a little slow but I'm getting it. I will chek voltage.

[Steve]

OK, reading through this again and looking at the meter again, yes, you are right, that "1" at the right is x1000, due to the scale label.

The others are right, with that meter, the best you are going to do is to check the output voltage. To do that, remove the three stator wires from their connections to the r/r. Mentally label them A, B and C, it does not matter which one is which. Run the bike up to 4-5,000 rpm, hold it at the same speed for your voltage measurements, you need to see how consistent the readings are. You should see over 70 volts AC (use the red 250 range at the bottom of the dial) between A-B, B-C and C-A.

Some time soon, splurge. Get a new meter. You don't even have to spend a lot of money. Here is one from Sears for $7.02.

There are, of course, many more from which to choose, but the big things you are looking for are "digital" and "auto-ranging".

.

[posplayr]

OK, reading through this again and looking at the meter again, yes, you are right, that "1" at the right is x1000, due to the scale label.

The others are right, with that meter, the best you are going to do is to check the output voltage. To do that, remove the three stator wires from their connections to the r/r. Mentally label them A, B and C, it does not matter which one is which. Run the bike up to 4-5,000 rpm, hold it at the same speed for your voltage measurements, you need to see how consistent the readings are. You should see over 70 volts AC (use the red 250 range at the bottom of the dial) between A-B, B-C and C-A.

Some time soon, splurge. Get a new meter. You don't even have to spend a lot of money. Here is one from Sears for $7.02.

There are, of course, many more from which to choose, but the big things you are looking for are "digital" and "auto-ranging".

.

That is a strang way to mark a meter; If it is 1M ohm FS then mark it that way. They are marking the scale on the first Major increment

[Guy]

What are you on about?
All analogue meters are marked that way.