Ohmmeter reading help please?

Question

I have digital multimeter. With Ohm dial setting on '200' I get a reading of .3 on a particular test across all of armature segment bars. Another test with dial setting on '200M' across shaft of armature and bars I get a reading of 1.6.

What do the readings mean and how many 'ohms' have I found.

Second question - how does someone know what setting to put th eohmmeter on before any test, i.e. do you just guess or what.

Thanks anyone.

Answer 1

? I've used a real multimeter, analog, digital is cook too...Always set to the highest and then come down. Know where ground is to put the black lead. Don't get confused with basic electrical work, sometimes their black is hot. In electronics red is B+/pos.

know the color code BBROYGBVGW..

Oh, M is usually meg, a lot.

Answer 2

You probably used the old analogue type meter.

Your readings look correct. If there is a low reading between the armature wire and the casing there is a problem.

An ohm meter passes a small current through whatever you are measuring and it reads the return current. If the return current is high there is a low resistance. Note that the analogue meter is marked from right to left.

For measuring things at home you will mainly use under 200 ohm. That is elements light bulbs etc. You can work it out by having a 1kW element on 110 VAC then the resistance should be around 10ohm with ohm's law. V=IR.

Otherwise resistors have colour bands to indicate their resistance. So you select the range to test in.

Motors normally also have low resistances. The 0.18 kW motors have higher resistances as they use smaller gauge wires that have more resistance.

You can't however measure anything with semiconductors as they react different to currents.

I use a Fluke 179 auto ranging multimeter and I never worry about selecting a range.

Hope this helps.