Lincoln ranger 8

Varmint1

New member
Picked up a ranger 8 over the weekend, have around 110-117 a/c volts at receptacle, very cold d/c at rod, can burn a 6011 on a/c with it turned all the way up to the 225 mark but still burns like it’s set at 70 amps. Check slip ring resistant and getting 4.8 ohms. But when measuring from slip ring to chassis ground I get nothing but if I touch the ring while I’m taking reading i do get around 160 thousand ohms, do I have a bad rotor? I’m getting about 34 volts a/c at brush leads.
 

Zephyr7

Active member
This might just be measurement error. Try two things to be sure:

1- poke the points of the probes in and twist a little, then hold while pressing them in with some force. On older gear, it’s common to have an oxide layer on metal parts that is resistive and will make measurements be off, and make them inconsistent. Using a sharp probe point and some force will help to pierce the oxide layer so that you can get reliable and consistent measurements.

2- the change in your measurement when you touch the ring might be due to capacitive loading from your body on the high-impedance meter. If it’s capacitive loading, you’ll see the reading drift over a few tens of seconds as your body capacitance charges up (or discharges).

If you don’t show a path to ground with your meter, then there shouldn’t be a path to ground when you touch the ring, except for through you which shouldn’t be completing a circuit in this case.

Bill
 

Varmint1

New member
I’m going to do some more testing, hopefully I won’t need to have the rotor rewound. Thanks Bill for the information
 

Varmint1

New member
Ok I did some thinking about the rotor, testing between rings I get 4.8 ohms, the book says to test one ring to chassis ground and I should get 500,000 ohms, I think that’s a miss print because I would get that if it’s dhorted to ground. Retested this evening, slip rings I get 4.8 ohms, calls (4-5 ohms) slip rings leads while running 35.8 vdc (37-46 vdc) check bridge rectifier 35.2 vac (36-43 vac). Little low I think is due to not at high idle. So I pulled all diodes out and wire brushed to remove any corrosion and tested, two shows open and two shows resistance both ways, my question is would it still try and weld like that?
 

Zephyr7

Active member
Are those diodes in a bridge rectifier that are showing “two open” and “two both ways” (that’d be shorted)? Sounds like the diodes are all bad, but the windings are ok. That’s good! Diodes are much easier to fix :)

I’d replace all the diodes. They should be fairly cheap, and it’s easy to get suitable new replacements even for old stuff.

Bill
 

Varmint1

New member
I’m going to replace all four diodes. Through air gas, and also I talked to Lincoln they are around 120 dollars apiece but found some on a web site for 52 dollars apiece. But for what I got this machine for I can put so money into it
 

Zephyr7

Active member
They must be awfully beefy diodes if they are $52 each.

Are you quoting through welding supply places or electronics supply houses? Welding places will probably charge more. I’d try calling galco industrial electronics and ask them. You might be able to save a lot of money that way.

Bill
 
Top