Author Topic: Question on voltage reg..... (Read 2647 times)

brcree · « **on:** August 23, 2011, 10:35:03 PM »

Has anyone up graded the stock voltage reg. on a 76 cb 750 to a more modern unit?

HondaMan · « **Reply #1 on:** August 23, 2011, 10:37:47 PM »

Some have, but they get mixed reviews. Avoid the ones that tout "increased alternator output" as they are sometimes shunt-type units, which will toast the alternator windings after a while. The 750 has a robust system as-is: if yours is having issues then we should talk about the broken thingie it is now harboring.

brcree · « **Reply #2 on:** August 23, 2011, 10:46:34 PM »

Thanks for the reply Honda man...as i try and remember correctly...when you turn the key to on you should get a magnetic pull from the stater...using a screw driver....correct?

strynboen · « **Reply #3 on:** August 23, 2011, 11:22:21 PM »

no the rotor gets mag..from the coil behind the rotor.

Bodi · « **Reply #4 on:** August 24, 2011, 05:51:51 AM »

"when you turn the key to on you should get a magnetic pull from the stater...using a screw driver"
In a way. What we generally call the "stator" is the three-phase output coil assembly mounted to the alternator cover. This alternator type, "induced field", uses an electromagnet to produce the magnetic field that makes the electricity. This electromagnet "field" coil is the inner coil assembly on the alternator cover. The rotor has various iron pole pieces in an aluminum casting, the iron bits bend the magnetic field from the field coil so it sweeps over the stator coil wires when the rotor turns.
The regulator turns the field coil power on and off depending on the electrical system voltage. "Upgrading" to an electronic field controlling regulator can not make more power and, as HM says, some new regulators work differently - they power the field coil all the time and control the output by wasting the extra power. This wastes engine horsepower and can cause burnt connections in a tired wiring harness.
With the key on you might feel some magnetic pull on a screwdriver if you hold it near the alternator cover. This is from the field coil though, not the stator.

brcree · « **Reply #5 on:** August 24, 2011, 11:28:34 AM »

Thanks guys...just tried the screwdriver on the part you suggested with key on....no magnetic pull at all........

TwoTired · « **Reply #6 on:** August 24, 2011, 11:43:36 AM »

Try using a thin feeler gauge blade.

magnum56 · « **Reply #7 on:** August 24, 2011, 11:44:47 AM »

Quote from: brcree on August 24, 2011, 11:28:34 AM

Thanks guys...just tried the screwdriver on the part you suggested with key on....no magnetic pull at all........

He said you "MIGHT" be able to sense the magnetic pull from outside the Alt cover.
Please do not consider "not" feeling the pull as a definite problem.

If you don't have one already, I would recomend investing in a "multi-meter" and review the maintence manuals for various test procedures there.

And always make sure you are preforming your tests with a fully charged battery.

brcree · « **Reply #8 on:** August 24, 2011, 11:46:54 AM »

I have the cover removed from the eng...........and will try the feeler guage. I'm using a meter as well....and know how to use one.

TwoTired · « **Reply #9 on:** August 24, 2011, 11:51:31 AM »

The field coil is an electromagnet. When it is provided with 12 V, it makes a magnetic field. The poles are (mostly) directed radially.

brcree · « **Reply #10 on:** August 24, 2011, 11:54:02 AM »

We are talking about the silver doughnut shapped unit in the middle of the cover ..correct? I used a small piece of wire...not copper....and still nothing.....The batt,. is at full charge. $:-\$

TwoTired · « **Reply #11 on:** August 24, 2011, 12:12:56 PM »

Can you measure the resistance of the field coil?

magnum56 · « **Reply #12 on:** August 24, 2011, 12:22:31 PM »

Quote from: brcree on August 24, 2011, 11:54:02 AM

We are talking about the silver doughnut shapped unit in the middle of the cover ..correct? I used a small piece of wire...not copper....and still nothing.....The batt,. is at full charge. $:-\$

Yes the "dough nut" is the field coil. It has to be "activated" by the regulator to produce the magnetic field.
As TwoTired has indicated, check the resitance of the field coil with the multi meter.

brcree · « **Reply #13 on:** August 24, 2011, 12:33:46 PM »

OK Mag...did the test no resis.. also did a volt check across the g,w,and black wires on the reg.....g to w 0....g to b 9.5 with key on

TwoTired · « **Reply #14 on:** August 24, 2011, 12:40:43 PM »

Measure the field coil resistance disconnected from the bike. S/B 6.8 Ω.

Zero resistance is a direct short. infinity is usually and open circuit. Meter leads have resistance, too.

brcree · « **Reply #15 on:** August 24, 2011, 12:51:26 PM »

Placed meter leads across both wires and got 0.01 reading.

TwoTired · « **Reply #16 on:** August 24, 2011, 01:47:23 PM »

If your report is accurate, then the field coil is shorted.

What meter scale are you using?
What does you meter's manual say is the display indication for opens or shorts?
What does the meter read with the probes touching and apart?

Cheers,

brcree · « **Reply #17 on:** August 25, 2011, 10:05:03 AM »

1. I have the meter setting at 20 DCV.....2. If a reading....its good....with just o in window ..or Infin....short. 3. 0.05.

KRONUS0100 · « **Reply #18 on:** August 25, 2011, 10:27:03 AM »

i have a new solid state voltage regulator, and a rectifier from Tony at OREGON MOTORCYCLE PARTS. they look like the stock pieces and they work great.

brcree · « **Reply #19 on:** August 25, 2011, 10:32:33 AM »

Kron...whats your price?...I thought about taking this rout.

TwoTired · « **Reply #20 on:** August 25, 2011, 10:56:03 AM »

Quote from: brcree on August 25, 2011, 10:05:03 AM

1. I have the meter setting at 20 DCV.....2. If a reading....its good....with just o in window ..or Infin....short. 3. 0.05.

Multimeters are labeled as such because they have multiple functions depending on the selector/scale used.

In basic DC cicuits there are three primary properties to be concern with: Resistance (R), Voltage (E, for Electromotive force), and Current (I). They behave in this relationship. E=I x R or the equation variations of I=E/R and R=I/E depending on which value you wish to derive from the other two properties. A multimeter can measure each of these if it is set up in the correct way.

You will not be able to measure resistance (Ω, or ohms) directly on a meter set up to read voltage (DCV, Direct Current Voltage)
You must set the meter to the lowest ohms scale (in order to read within that expected range). First establish the meter reading with probes apart, then with probes touching directly to each other and note those readings. THEN, you can connect the probes to the device to be measured and record the display indication.

I asked you to measure the resistance of the field coil. There will be no voltage in the coil if it is disconnected from the bike. So, a meter set to read voltage won't find any, and I can't use your report to help you.

Cheers,

brcree · « **Reply #21 on:** August 25, 2011, 11:22:25 AM »

OK Two...I'm not giving up that easy......Plugged field coil up ....on meeter there is a ohms section....with a dot with nothing by it, a dot with 20k/2000 next to it and then a dot with just 200. With key on the meter set to 200 reads 0.65.....meter set to dot with nothing reads 0.06.

bollingball · « **Reply #22 on:** August 25, 2011, 11:35:21 AM »

I'm using a meter as well....and know how to use one.
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TwoTired · « **Reply #23 on:** August 25, 2011, 11:36:25 AM »

Post a pic of your meter face. Or, tell me the make and model of it.

Sorry, I still can't interpret what you are telling me about your measurements in a meaningful way.

Cheers,

brcree · « **Reply #24 on:** August 25, 2011, 11:40:47 AM »

Not try-en to be a bugger there Two...just want this thing to run like it should....not much summer left! The meter is a Cen-Tech...item # 98025.

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Author Topic: Question on voltage reg..... (Read 2647 times)

bollingball