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A tool for measuring DC current?

Started by Jeff K, Mon 20, Sep 2010, 18:59:45

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Jeff K

What do YOU use to measure DC current? I have a relay that is running hot and I'd like to get an idea how much current is going through it, but my fluke only goes up to 10 amp. It has a 20 amp fuse and its not blowing but it seems odd that it gets so hot.

Jeff K

Problem solved. The relay was bad. I was having trouble with my fuel pump not coming on. I swapped relays for the one next to it, but it was still intermittent. So, after checking all the connections I decided to put a new relay in place of the hot one. Ta Da. I had higher hopes for those bosch relays.
I still want a good way to measure DC current.

Challenger

I have an automotive in dash 50 amp meter with about 6" of wire on each terminal, a female spade on one and a female spade on the other that I use in the shop to check current draw on relays and fuses. With a tiny flat blade screw driver, remove the power in spade from the connector body, plug the meter into the relay and the incoming wire to the other side of the meter. 

Jeff K

Quote from: Challenger on Mon 20, Sep 2010, 19:44:10
I have an automotive in dash 50 amp meter with about 6" of wire on each terminal, a female spade on one and a female spade on the other that I use in the shop to check current draw on relays and fuses. With a tiny flat blade screw driver, remove the power in spade from the connector body, plug the meter into the relay and the incoming wire to the other side of the meter. 

Yeah I was thinking about going a similar route, like a 30 analog panel meter.

GreenLantern57

Hit the pawn shops and get a better meter. My experience on relays is the coil going bad and that is where all the heat comes from.  The older the meter, the better you can talk the pawn owner down.

Shockbushing Gary

I have an old Fluke 77. They did not have integral fuses then. Once while chasing a problem I hooked it up and saw 75 amps. I unhooked that one right away.
I find I can kind of tell when the current flow is real high by the size of spark it makes. This just tells me how big an ammeter I need. Below 20 amps- the Fluke, briefly. Above 20 amps, I have a clamp-on. The Fluke is good for milliamps, too, but I seldom use that.
I think the newer DMMs will go 20 amps without smoke getting out of 'em... and they're all fused so you can't fry 'em

Thunderbolt

most are made in China or somewhere like that and are not too expensive.  I have one hiding in the shop somewhere.  :)  Just don't remember the range right now..........

Robert

#7
I have a old fox meter sold by mac tools must be 20 years old but its the best does 9 amps on one scales and then 32 amps on the other, anything over that I have a battery tester/ carbon pile that is inductive 1 to 100 or 0 to 500 amps. For small draws I dont like inductive but I just bought a Matco tools inductive amp meter 0 to 30 amps. I needed it for the small draws on cars that keep the battery draining and you cant tell where there from. This you can put around a wire and tell the draw without interrupting the circuit. It has volts ohms amps ac/dc and just a little bigger than a normal inductive clip.  After buying this inductive I still like the Fox meter with that you have to hook into the circuit the reason even though the new inductive is pretty good you still have to fiddle with it to obtain a accurate reading like zeroing the meter in the area you are using it, the meter just clips in line very accurate. Especially for loads below 1 amp. I had the hardest time finding a accurate amp meter for the lower amperage if you are not using it for battery draw or just want a approximate reading the inductive will be fine
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