How to test? |
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How to test? |
oldschool |
Dec 30 2014, 05:28 PM
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#1
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Advanced Member Group: Members Posts: 3,372 Joined: 29-October 08 From: P-town Member No.: 9,705 Region Association: Southern California |
So I do I test this thing (IMG:style_emoticons/default/confused24.gif)
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Elliot Cannon |
Dec 30 2014, 05:55 PM
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#2
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914 Guru Group: Retired Members Posts: 8,487 Joined: 29-December 06 From: Paso Robles Ca. (Central coast) Member No.: 7,407 Region Association: None |
Test it in another 914. Don't you have more than one? (IMG:style_emoticons/default/biggrin.gif)
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Rand |
Dec 30 2014, 06:07 PM
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#3
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Cross Member Group: Members Posts: 7,409 Joined: 8-February 05 From: OR Member No.: 3,573 Region Association: None |
Throw it in a lake. If it floats, it passes. Then get a new one, and wonder what else is wrong.
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oldschool |
Dec 30 2014, 06:51 PM
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#4
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Advanced Member Group: Members Posts: 3,372 Joined: 29-October 08 From: P-town Member No.: 9,705 Region Association: Southern California |
(IMG:style_emoticons/default/agree.gif) ..I have a few in my stash....just want to know if I should throw it away... (IMG:style_emoticons/default/evilgrin.gif)
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oldschool |
Dec 30 2014, 06:52 PM
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#5
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Advanced Member Group: Members Posts: 3,372 Joined: 29-October 08 From: P-town Member No.: 9,705 Region Association: Southern California |
No.... (IMG:style_emoticons/default/confused24.gif) just one now. (IMG:style_emoticons/default/laugh.gif) |
Spoke |
Dec 30 2014, 07:56 PM
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#6
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Jerry Group: Members Posts: 7,052 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None |
So I do I test this thing 2 ways to test it. Put it in the car; start the engine and see if it regulates the battery voltage to about 13.5 to 14V. Must measure at the battery. This assumes the alternator and all wiring are ok. Test it on the bench. A bit more involved. Put a DC voltage across D+ to D-. Put a load resistor of some value equal to the resistance of the alternator armature; maybe 100 ohms between DF and D-. Vary the dc voltage from 12 to 15V while monitoring DF to D-. Below 13.5V (D+ to D-) the voltage from DF to D- should be near the DC input voltage. Above 14V (D+ to D-), DF should be zero volts. I've never tested one like this but this method should work. (IMG:style_emoticons/default/smile.gif) |
oldschool |
Dec 30 2014, 10:16 PM
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#7
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Advanced Member Group: Members Posts: 3,372 Joined: 29-October 08 From: P-town Member No.: 9,705 Region Association: Southern California |
Thanks Jerry I guess I'll just put it back and do the test. (IMG:style_emoticons/default/piratenanner.gif)
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r_towle |
Dec 30 2014, 10:26 PM
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#8
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Custom Member Group: Members Posts: 24,624 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
With a tester, how else....?
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stugray |
Dec 31 2014, 02:28 PM
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#9
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Advanced Member Group: Members Posts: 3,825 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
These are basically a relay with an op-amp comparator to control the position.
Above ~14 volts, the relay should open (take the alternator input away from the battery) Below ~13 volts, the relay should close (putting the alt output back onto the battery). The deadband (should not change state) is between 13-14. So if you had a variable voltage power supply, you could check the transition points. I know the older units in the type-I engines were physical relays and you could hear them buzzing when they were working but hard to hear over the engine noise and are not doing anything unless running. The newer ones you can buy now (solid state) have no moving parts so make no noise. |
oldschool |
Dec 31 2014, 03:18 PM
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#10
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Advanced Member Group: Members Posts: 3,372 Joined: 29-October 08 From: P-town Member No.: 9,705 Region Association: Southern California |
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oldschool |
Dec 31 2014, 03:18 PM
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#11
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Advanced Member Group: Members Posts: 3,372 Joined: 29-October 08 From: P-town Member No.: 9,705 Region Association: Southern California |
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