MTFCA Forum

I have this generator current tester. I’m not sure if it’s for T’s or how to use it. Any ideas?
Tom

Had one similar some years back, easy to use, just put the back of it along any live wire or + battery cable and will read the amps in the circuit.

Thank you, I can’t wait to see the current draw when using the electric starter

If you use that to measure current draw, you still won't know how much current the starter pulls, and you'll destroy the meter, to boot. Even just spinning and not engaging the motor, the amperage will wildly exceed your meter's rating.

Agree with Scott on that, fine for checking the running amps but would fry it for cranking amps.

Thank you guys for saving my tool. I would never though the starter would draw over 50 amps
Tom

I am glad you did, too.

FYI...70 amps free running, 150-160 Amps cranking engine and 450 Amps stalled at 12 pounds of torque. A really good starter will push a little over 13 pounds, and will have even higher amperage, but 12 was the spec.

Tom. I have a old Sears inductive pickup ammeter # 2173 and it is great for checking starter current. Generator output and current draw from lights, Horn ect. NAPA sells one just like it model # 700-1712 there are 10 on E-Bay now brand new in the box for $10.95.free shipping. I ordered another one for a spare. Has two scales both zero center. 75- 0-75 & 400-0-400 amp just slips the over wire no physical connection. two slots one for small wire one for large starter cable.

to anyone who really wants to check their starter's amp draw, I would pose a simple question: why?

if the starter starts the car, it starts

if the starter doesn't start the car and proper cables and ground is in place, repair the starter

I am set up to repair starters (but do NOT solicit work any more) and the ONLY reason I ever tested AMP draw on a starter was to verify proper torque output and correct amp reading was given at full stall condition when the job was done (and they always did).

As an aside, I believe far too many engines are rebuilt (be cause it's old and am sure it needs it), and now we can ad to the list to start worrying about starters because a current reading is mis-diagnosed or mis-applied to a bad set up.

If it starts, then go have some ice cream and worry about something else...

Scott. I agree. The only reason I would check it would be to establish a base line current when the starter was operating normally for later comparison if You started to have problems. If it ain't broke don't fix it.

Jim

I understand what you're trying to accomplish, but understand that in the car, you are not testing the starter amperage. You are testing the starting circuit amperage. All you have to do is have a starter button start to fail, creating resistance through that contact resulting in a voltage drop and your current measurement will be very misleading. If you measured the amperage then, is everything good? do you need to rebuild the starter? No, you need to rebuild the starter button.

Testing the starter current on a test stand tests the starter. Testing current with the starter in the car tests the entire system which includes the starter. All it will tell you is there is a fault in the system (or not). A slow operating starter tells you the same thing. And that's my point.

I do get it that some folks like a science project (a good way to learn things!), but to analyze the results, you need to account for the variables...and this project has a number of variables.