Where all do YOU use an amp clamp?

[signcrafter]

To go along with my other post about amp clamps I thought I would start this one to see where all these can be used and how useful they actually are. I know they make a low amp and high amp version so be sure to specify which you use where if you could.

I'm mainly looking at the high amp clamp for now for testing things like the charging system. Since I can use my fluke for testing up to 10 amps.

 

[ddawg16]

There are two kinds of amp clamps. AC and DC.

So are you talking about just DC applications for automotive?

 

[kamesama980]

high-A capable AC/DC cheap meter from JCwhitney
I've used it on charging/starting system down to battery parasitic loads. The few times I've tried it, it's accurate below .25a. Accurate as a picoscope amp clamp anyway.

Actually I haven't used it much, especially since getting out of school. Not the kind of problems I've had, vehicular or otherwise. *knocks on wood*

 

[signcrafter]

There are two kinds of amp clamps. AC and DC.

So are you talking about just DC applications for automotive?

Just for vehicle testing so I believe just DC. Although aren't there some alternator tests that require reading AC?

 

[firebox40dash5]

As long as you've got an internally-rectified alternator, there shouldn't be AC outside the case... I don't think, anyway. Kinda a moot point, I don't think I've ever seen a DC clamp that couldn't do AC, unlike the other way around. There is AC involved in stuff like Hall-effects, but I've never seen a test of amperage on them, usually AC volts. You'd need enough room to get the clamp around just one wire anyway, which would often be an issue.

Now that I think about it, we've got a diesel Dodge waiting on an engine that kills both its batteries in a matter of hours... I should try out my clamp on it.

 

[Buckgnarly]

Checking the amps on my plow truck's alternator, and the drain by my plow pump and winch.

 

[MLB0611]

I use my low amp clamp to find parasitic draws,and with my scope to check primary ignition coil currents, amp loads on circuits and Fuel pump starting and running currents.

Hi amp is mostly used for starter amp draws. just diagnosed a bad starter on a acura yesterday complain was slow crank intermittently

 

[zakmartin]

It's useful when you're installing high-wattage amplifiers on your car to make sure that you're not over-burdening your power and ground wires.

 

[richfinn]

Heater plug draw on diesels

In tank electric fuel pumps

Starter/alternator current

Wiper motors/drop glass motors if your chasing blown fuses

I use my current probe and scope for ramping injectors/comparative compression/ignition systems.

 

[bsaint]

I only use a current clamp in induction applications when I don't have an LCR.

Normally I use the formula for current and power to figure out my current draw.

 

[zkling]

I use mine to measure amperage.

Primarily for electric motors, welders, not much car stuff, but I'm not a pro so YMMV. Typically with things like parasitic draw I will just measure voltage and calculate what is needed.

I've also used it quite a bit to determine energy cost for appliances.

 

[Rookie2]

I used a uei dl100 , other than always having to '0' it all the time it was great for automotive work.

 

[theoldwizard1]

It's useful when you're installing high-wattage amplifiers on your car to make sure that you're not over-burdening your power and ground wires.

Those transients are too fast to catch with any kind of inductive pick up.

 

[theoldwizard1]

If you have a current pick up connected to a PicoScope, you can tell if one or more cylinders are low on compression.

Difficult on COP.

 

[zakmartin]

Those transients are too fast to catch with any kind of inductive pick up.

I'm talking about one of these:

Are we talking about something else? lol

 

[Bikes&Bowties]

Simple starting and charging tests. Ill be honest I have only used it once or twice out of school.

 

[shampoop]

This guy is pretty cheap and awesome for basic at home starter/alternator testing.

http://www.tooltopia.com/kd-tools-2423.aspx

 

[GTA Matt]

Fuel pumps, starters, alternators, relative compression tests, injectors, ignition coils, transmission shift solenoids, parasitic draws, blower motors, etc. Basically anything electrical in a car. If it can be tested from the fuse box, pcm or wiring harness without having to access the component, it saves time and gives absolute certainty in the diagnosis.

 

[basspro]

I use an ampmeter all the time to check AC/DC motors in our plant. Everything very small up to 400 amps. All sorts of voltage ranges in AC, anything from 120V to 580V. Most often this is on three phase motors to see if a phase is higher or lower than another.

 

[sdguy55]

I'm talking about one of these:

Are we talking about something else? lol

Unless your doing a pink noise test (or a single bass tone for sub's) at max volume, he's right. Music is to dynamic to get a reliable reading for an amp. And an inductive amp clamp is ment more for things that pull a set amount of amperage. Sure it will pick up changes in amperage but not fast enough for music. A scope is the only thing fast enough I would think

 

[ol'Red]

Myself all time application on glow plug harnesses, but have used them on countless applications.

 

[Danglerb]

I use a Sears Craftsman 82369, always needs to be zeroed, but seems to track ok within 0.010 amp, puts it just inside the usable, especially if you reset the zero/check zero, even for parasitic drain testing.

I use it a lot, so easy to snap the clamp over a wire and find out what the current flow is, compared to opening the circuit and putting in a series meter.

Most common use, battery charging, often just over the PLUS lead from my charger which says 2/20 amps charging, but meter tells me 2 setting can be as much as 5 amps on a low battery, and 20 setting starts at 20 amps and drops as soon as about 80% charged.

***

Car audio is so full of hype, major power draw is from bass under 100 hz, and the envelope of the transient isn't going to be much higher if any. Turn on is likely the highest draw by a large margin.

 

[zakmartin]

Unless your doing a pink noise test (or a single bass tone for sub's) at max volume, he's right. Music is to dynamic to get a reliable reading for an amp. And an inductive amp clamp is ment more for things that pull a set amount of amperage. Sure it will pick up changes in amperage but not fast enough for music. A scope is the only thing fast enough I would think

Actually, that's exactly what I use it for. I have a tone disc that I play to set the gain on my amplifiers (usually JL-Audio) and run them at a steady high volume while using the amp clamp and a multimeter to test the main power wire and the wires coming from the power distribution block to see how many amps I'm drawing and then I decide whether to run the ground back to the negative battery post or just to the body, since when you're not running in parallel, high amperage draws from aftermarket stereo systems can be invisible to the ECU on newer cars. I also want to make sure that the wiring I'm using is properly gauged for the amplifiers I'm using.