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Testing alternator out of car
ken555 - 6/10/15 at 02:38 PM

How can you test an Alternator off the car?
Need to see it's ok, before I go making custom mounts for it.

I'm thinking of fixing the alternator in the vice.

Jump leads to a battery, with thinner wire/bulb to the ind connector, and a live to the L connector. Thats the easy bit.

But how to spin it?

Would a electric/air wrench have the power to drive it off the front nut, or do I need to arrange some form of motor/belt setup?

Maybe a starter motor would do.
Looking for a locost solution, so things lying around in the garage.

nick205 - 6/10/15 at 02:49 PM

Securing it in a vice should be OK. Maybe a weight on a wire or string around the pulley would exercise it for you to test.

theconrodkid - 6/10/15 at 02:57 PM

you can check most of the workings by putting a live to the exciter terminal....thats the exciting bit and earthing the body,the pulley should be hard to turn as you have livened up the magnets

cliftyhanger - 6/10/15 at 02:57 PM

Not certain about this but.....

If it supplies 12v (usually 14V) and say 40A that would make it produce about 500watts. Probably 60% efficient, so that would need 800watts.

However, it you use a fully charged battery, it will put out a lot less current, so an electric drill should do it? Possibly! Need to spin fairly fast, think 3000rpm, but may produce charge at half that.
(alternator pulleys are much smaller than crank pulleys, so the alternator spins 3-5times faster than the cars rpm, give or take)

ken555 - 6/10/15 at 03:02 PM

quote:
Originally posted by nick205
Securing it in a vice should be OK. Maybe a weight on a wire or string around the pulley would exercise it for you to test.


Sort of Rip cord / Pull start style

nick205 - 6/10/15 at 03:19 PM

quote:
Originally posted by ken555
quote:
Originally posted by nick205
Securing it in a vice should be OK. Maybe a weight on a wire or string around the pulley would exercise it for you to test.


Sort of Rip cord / Pull start style


Yup, that's what I was thinking....or an electric drill, but take care!

britishtrident - 6/10/15 at 03:50 PM

The back street reconditioned used to use a rig with an old Hoover Twin Tub motor and Hoover belt.

You can test the diodes easily enough with multimeter, the brushes are aa cheap wearing part so change them as a matter of course anyway.

ragindave - 7/10/15 at 10:09 AM

Perhaps use a drill with a socket?

coyoteboy - 7/10/15 at 12:06 PM

All seems backward to me. If it's knackered you'll buy a new one or get it reconned, so just make the brackets to suit and deal with the potential of a fault later.

ken555 - 7/10/15 at 12:50 PM

quote:
Originally posted by coyoteboy
All seems backward to me. If it's knackered you'll buy a new one or get it reconned, so just make the brackets to suit and deal with the potential of a fault later.


That's means trying to find the exact model in the scrapyard again. (I'm Scottish I can't help not wanting to spend money)

I was planning to test then fit/make bracket

ReMan - 7/10/15 at 01:00 PM

quote:
Originally posted by ken555
quote:
Originally posted by coyoteboy
All seems backward to me. If it's knackered you'll buy a new one or get it reconned, so just make the brackets to suit and deal with the potential of a fault later.


That's means trying to find the exact model in the scrapyard again. (I'm Scottish I can't help not wanting to spend money)

I was planning to test then fit/make bracket


This is what I was thinking too.!!
Unlesss you have reason to supect its a duffer, assume its good and get on

britishtrident - 7/10/15 at 01:55 PM

Alternators are generally easy enough to fix
On some Lucas-Magneti Marelli alternators you can change the brushes and regulator by simply removing two screws, with the alternator on the car although with most the alternator has to be removed from the car and the back cover removed.
Renewing the diodes generally simple but involves some very simple soldering but needs a powerful soldering iron.