multimeter help please - SV650.org

Stu · 29-01-09, 10:23 PM

How do I us a multimeter to find out if a +ve and -ve wires are shorting together?
Thanks

29-01-09, 10:25 PM

more info required

yorkie_chris · 29-01-09, 10:34 PM

First guess resistance test. But yeah more info!

29-01-09, 10:37 PM

You need to put the black lead from your multimeter to an earth point (somewhere on the frame), then put the red lead on the ends of the two cables in turn.

Only the +ve should have a voltage reading if the switch for the circuit is turned off. If you have a voltage reading on the -ve wire, they are shorting.

Note: The switch for the circuit you are testing must be turned off to do this test!

Sid Squid · 29-01-09, 10:42 PM

Are you doing a leak test?

If yes, then set the meter to a resistance scale, (ohms, the Omega sign), a range of about 20 ohms is useful, make sure the bike is switched and off remove the leads from the battery, ensure that nothing touches the battery terminals. Clip the meter leads to the bike's battery leads, testing perfection requires no continuity at all, the real world says you may get a few ohms. If you get a significant reading disconnect the reg/rec, if the reading drops off the rectifier diodes are leaky.

29-01-09, 10:43 PM

tutorial here
http://www.ladyada.net/library/metertut/index.html
hope that helps

Stu · 29-01-09, 10:56 PM

Quote:

Originally Posted by Sid Squid

Are you doing a leak test?

If yes, then set the meter to a resistance scale, (ohms, the Omega sign), a range of about 20 ohms is useful, make sure the bike is switched and off remove the leads from the battery, ensure that nothing touches the battery terminals. Clip the meter leads to the bike's battery leads, testing perfection requires no continuity at all, the real world says you may get a few ohms. If you get a significant reading disconnect the reg/rec, if the reading drops off the rectifier diodes are leaky.

thanks all, but we have a winner

bit sneaky posting in SV tuning, but I'm soldering a gerbing wiring harness (I feckin hate soldering

) so want to make sure I'm not shorting any wires.

So as you say set the MM to Omega - 200 is the smallest and it reads 1 if I short the multimeter it goes to 00.5 so just replicate that with my wiring & hope it stays at a big fat 1

Cheers me dears

Sid Squid · 29-01-09, 11:00 PM

200 ohms is fine. The shorted meter reading you get could be used as a correction, but a reading that small won't affect things.

Stu · 29-01-09, 11:02 PM

Hey it works to ensure I've got a good connection too. i.e. make sure it does fall to 0 instead of stay at 1

Sid Squid · 29-01-09, 11:11 PM

I could do nothing else but recommend connecting the leads of the meter to whatever it is that you're trying to measure.

It's kinda the reason for having the wires on the meter see?

29-01-09, 10:23 PM	#1
Stu Trinity Mega Poster Join Date: Jun 2006 Location: Guildford Posts: 8,027	multimeter help please How do I us a multimeter to find out if a +ve and -ve wires are shorting together? Thanks

29-01-09, 10:25 PM	#2
Kilted Ginger Guest Posts: n/a	Re: multimeter help please more info required

29-01-09, 10:34 PM	#3
yorkie_chris Noisy Git Mega Poster Join Date: Apr 2007 Location: Halifax/Leeds Posts: 26,645	Re: multimeter help please First guess resistance test. But yeah more info! __________________ Currently Ex Biker Now rebuilding a 63' fishing trawler as a dive boat

29-01-09, 10:37 PM	#4
Learningcurve Guest Posts: n/a	Re: multimeter help please You need to put the black lead from your multimeter to an earth point (somewhere on the frame), then put the red lead on the ends of the two cables in turn. Only the +ve should have a voltage reading if the switch for the circuit is turned off. If you have a voltage reading on the -ve wire, they are shorting. Note: The switch for the circuit you are testing must be turned off to do this test!

29-01-09, 10:42 PM	#5
Sid Squid No, I don't lend tools. Mega Poster Join Date: Jul 2003 Location: Skunk Works, Nth London Posts: 8,680	Re: multimeter help please Are you doing a leak test? If yes, then set the meter to a resistance scale, (ohms, the Omega sign), a range of about 20 ohms is useful, make sure the bike is switched and off remove the leads from the battery, ensure that nothing touches the battery terminals. Clip the meter leads to the bike's battery leads, testing perfection requires no continuity at all, the real world says you may get a few ohms. If you get a significant reading disconnect the reg/rec, if the reading drops off the rectifier diodes are leaky. __________________ If an SV650 has a flat tyre in the forest and no-one is there to blow it up, how long will it be 'til someone posts that the reg/rec is duff and the world will end unless a CBR unit is fitted? A little bit of knowledge = a dangerous thing. "a deathless anthem of nuclear-strength romantic angst"

29-01-09, 10:43 PM	#6
theshed Guest Posts: n/a	Re: multimeter help please tutorial here http://www.ladyada.net/library/metertut/index.html hope that helps

29-01-09, 11:00 PM	#8
Sid Squid No, I don't lend tools. Mega Poster Join Date: Jul 2003 Location: Skunk Works, Nth London Posts: 8,680	Re: multimeter help please 200 ohms is fine. The shorted meter reading you get could be used as a correction, but a reading that small won't affect things. __________________ If an SV650 has a flat tyre in the forest and no-one is there to blow it up, how long will it be 'til someone posts that the reg/rec is duff and the world will end unless a CBR unit is fitted? A little bit of knowledge = a dangerous thing. "a deathless anthem of nuclear-strength romantic angst"

29-01-09, 11:02 PM	#9
Stu Trinity Mega Poster Join Date: Jun 2006 Location: Guildford Posts: 8,027	Re: multimeter help please Hey it works to ensure I've got a good connection too. i.e. make sure it does fall to 0 instead of stay at 1

29-01-09, 11:11 PM	#10
Sid Squid No, I don't lend tools. Mega Poster Join Date: Jul 2003 Location: Skunk Works, Nth London Posts: 8,680	Re: multimeter help please I could do nothing else but recommend connecting the leads of the meter to whatever it is that you're trying to measure. It's kinda the reason for having the wires on the meter see? __________________ If an SV650 has a flat tyre in the forest and no-one is there to blow it up, how long will it be 'til someone posts that the reg/rec is duff and the world will end unless a CBR unit is fitted? A little bit of knowledge = a dangerous thing. "a deathless anthem of nuclear-strength romantic angst"

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