Bench Testing

[acbrock]

Ok I am slightly embarrassed to ask this question but rather that ruin everything....

So I have lots of components out of the car for repair cleaning.  Before I put them all back in I need to test them.  I bought a power switcher so I can run a 12 Volt supply on my Desk.  Question...  Can I just connect the wires to each component and see if it runs?  Clock, Wiper Motor, Blower etc?  Or does each thing need a specific amount of power?  I just dont want to blow things up!  Not great with Electrical stuff and have read a bunch but I just dont feel confident in the answers I have seen.  So before I destroy parts I cannot replace I thought I would just throw it out there and feel the shame!
Thanks for any info
Aaron

[BobH]

Hello Aaron, electrical equipment draws as much power as it needs to operate, a clock takes very little power, (amps) whereas a blower motor can take a considerable amount.  A wiper motor will be somewhere in between, although don't forget this has a separate +ve feed to home the wipers, so may not be easy to test on a bench, you may have to experiment

The point being, a bench power supply needs to be able to produce sufficient power for the item you're testing, no good using a 5A supply to try and run a motor that needs 10A

An indication is to look at the size of the fuses protecting the various pieces of equipment, there's a list in the tech manual, although fuses usually feed more than one item, one high power item, and several smaller power items, you'll get an idea of the power consumption of most of the equipment

Also don't forget that a car battery will supply over 14V, so your power supply needs to be adjustable up to probably 15V, so probably a 12 to 15V 30A power supply should suffice for most items you'd want to test

Unless you're intending to make a career out of this, might be easier to just test everything directly from a car battery

You wont be able to test a starter motor, from a bench tester, these take a humungous amount of current!

[rwmastel]

I bought a power switcher so I can run a 12 Volt supply on my Desk.

Aaron,

If you provide the details of this "power switcher", then smart people like BobH could give even better advice.

[acbrock]

Ok cool let me get the specs.  But I might just go with going straight off the battery since I have it out of the car...
Thanks!
A

[acbrock]

Specs on the Power Converter.  I did just try it on the clock and it fired up and started ticking.  So the clock repair was good!  Wahoo...
Specs:
RatedLoad: 600W
Output Voltage:DC12V
Output Current: 50A Max
Input Voltage 110/220
Adjust Range +-5%

$40 bucks on Amazon....

[BobH]

That's absolutely fine for everything you want to test, it should have some form of internal fuse or current limiter, which is safer than testing direct from a battery

[rwmastel]

Aaron,

You started off this thread with saying "Not great with Electrical stuff ".  I consider myself the same.  I've never bench tested anything out of a car.  How do you provide a ground connection when bench testing?  (Referencing your wiper motor post, where you said which pin gets ground.)

[merrill]

might be obvious but be sure to put the correct rated fuse inline when testing an item.

just in case

[acbrock]

The Power Converter has a Ground.

[BobH]

Aaron,

You started off this thread with saying "Not great with Electrical stuff ".  I consider myself the same.  I've never bench tested anything out of a car.  How do you provide a ground connection when bench testing?  (Referencing your wiper motor post, where you said which pin gets ground.)

Hello Rodd, sorry if i'm explaining this like a school teacher, but i find if i read something really simple it makes much more sense to me and sinks in, than when i read very short descriptions, where i'm left still confused, and asking questions, and need to go away and google

If you think about the car electrics, the battery terminal -ve is connected to ground, so all exposed metal and anything bolted to it has a -ve supply (+ ground cars, are the opposite)

Cars are almost unique, in that the -ve is supplied via the car metalwork, rather than having a separate -ve wire running to all equipment.  Almost every other situation where mains or battery electricity is used, such as your house, power tools, or an alarm system, uses separate +ve and -ve wires running everywhere

The +ve battery terminal connects, via fuses and switches or relay contacts to the various items of equipment, generally to a terminal of a plug, spade terminal or screwed connector, on the equipment, and the
 -ve is supplied either via the metal casing of the equipment when it's bolted to the car, as is the case with the wiper motor, or via another pin on the plug or connector, as is the case with the clock. 

Most  equipment is switched +ve, with a permanent -ve, or sometimes the opposite, like the horn, which has a permanent +ve and a switched -ve

Still awake?

The bench tester is just a 12V supply, it has two leads, a +ve and a -ve, with a crocodile clip or probe on each end.  The +ve lead will connect to the equipment +ve terminal, on the plug pin or terminal, and the -ve lead will connect to the case of the equipment, where the equipment is grounded through the case, or on the -ve contact pin on the plug or terminal

When the tester supply is switched on, bingo, you've completed the circuit

[acbrock]

BobH I love the long School Teacher explanations!  Even if I did understand it reading that gives me a better understanding and the ability to explain it to someone else!