| nighthawk 550 electrical problem [message #448875] |
Sun, 25 September 2005 21:46 |
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krusty kritter Wrote:
> jlpridge wrote:
> -
> The battery is brand new as of monday. I am purchasing a multimeter
> today to start testing stuff. I have not received my clymer manual
> yet
> so I am not sure how to test the rectifier and the stator. If any of
> you have any info on that it would be most helpful.-
>
> Charging voltage test:
>
> With a fully charged battery installed, start the engine. The
> headlights must be on to load the alternator. Hook a voltmeter across
> the battery with the voltmeter on a 15 to 20 volt DC scale. As you rev
> up the engine, the
> voltage should rise from 12 volts to about 15 to 16 volts. Then the
> voltage should drop off sharply. Roll off the throttle and roll it
> back
> on and the voltage should rise and sharply fall each time you do this.
> The charging voltage test will prove that the voltage regulating
> circuit works.
>
> Open circuit test:
>
> With the alternator plug disconnected from the voltage regulator, hook
> your voltmeter across any pair of AC output wires. There should be
> three AC output wires. The stator is Y-wound with a floating neutral,
> so the AC current goes from A phase to B phase to C phase and you can
> read the same AC voltage across any pair of wires. You should read
> around 90 to 120 volts AC as you rev the engine up. DO NOT RIDE THE
> MOTORCYCLE WITH THE AC OUTPUT PLUG DISCONNECTED. You can fry the
> insulation on that expen$ive stator.
>
> Stator continuity test:
>
> Set the ohmmeter on the R X 1 scale. As above, it's a Y-wound stator
> with a floating neutral, which means it's not supposed to be grounded
> to the engine. Check continuity on R X 1 scale from any wire to any
> other wire. It should be around 1 ohm. If you have a digital ohmmeter,
> you may not be able to zero out the lead resistance, so the resistance
> might be around 2 or 3 ohms. No problem.
>
> Switch to the R X 1000 scale and check all three leads to the engine
> block. You shouldn't get any reading.
>
> About the rectifier part of the RR unit:
>
> There are six power diodes inside the rectifier regulator. They change
> the AC input to a DC output. AC comes in through three wires, and DC
> comes out of two wires. Sometimes the rectifier case has to be
> grounded
> to the sheet metal plate that it's bolted to. If you look at bolt
> holes
> in the plate, check to see if all the paint has been removed around
> one
> of the bolt holes. That's a grounding point.
>
> Also, look at the back of the rectifier regulator. If it has some
> white
> sticky stuff on the back, that's heat sink compound that was used to
> transfer heat from the rectifier regulator unit to the sheet metal
> plate it's bolted to. Diodes get hot due to internal resistance, so
> the
> heat is radiated to the air through the fins and conducted to the
> sheet
> metal plate.
>
> The diodes are arranged in a three phase full wave configuration. If
> you look at the diagram on www.electrosport.com, you'll see the three
> AC inputs attach between pairs of arrowhead symbols. Those are the six
> power diodes.
>
> The convention is that the input current can only flow in the
> direction
> of the arrowheads.
>
> The diode test:
>
> This works best with an analog ohmmeter, as some digital meters won't
> read a diode correctly. With the ohmmeter on the R X 1 scale, check
> from each AC pin in the alternator input connector on the voltage
> regulator to the DC positive output pin.
>
> You should be able to tell the AC input connector from the DC output
> connector because it's probably impossible to hook the AC input
> conector to the DC output connector, the connectors should be "keyed"
> differently.
>
> To check the first three diodes, touch the black lead's probe to the
> AC
> input pin and the red lead to the DC output pin. If you don't get a
> reading, check with the black lead from the AC input pin to the DC
> output pin.
>
> You must get the SAME reading from each AC input pin to the DC output
> pin. It might be around 15 ohms, but I can't say for sure because the
> battery in an ohmmeter biases the diodes and causes different readings
> depending on the ohmmeter. If you don't get a reading, that probably
> indicates a blown out diode.
>
> Now, reverse the leads and check the other three diodes. Whatever lead
> gave you continuity from the AC input pin to the DC output pin is the
> wrong lead, so reverse the leads and check from the AC input pin to
> the
> DC negative ground pin. Again, you must get the same low reading from
> each AC input pin to the DC negative output.
>
> You should NOT get a reading in both directions, that indicates a
> shorted diode. You SHOULD get the SAME reading through all six diodes,
> going first from the AC input to the DC output to check the first
> three
> diodes, then reversing the leads and checking from the AC input to the
> DC negative side.
Krusty,
I tested the rectifier this morning according to electrex's chart
and the rectifier passed. Then I checked the stator according to your
instructions and the three tests of the three yellow wires revealed 0.0
ohms. According to this the stator is bad right?
--
jlpridge
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| Re: nighthawk 550 electrical problem [message #448876 ] |
Mon, 26 September 2005 00:27 |
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jlpridge wrote:
> I tested the rectifier this morning according to electrex's chart
> and the rectifier passed. Then I checked the stator according to your
> instructions and the three tests of the three yellow wires revealed 0.0
> ohms. According to this the stator is bad right?
If you are on the R X 1 scale and you read 0.0 ohms from any yellow
lead to any other yellow lead, that definitely suggests that the stator
windings are shorted out. You should get *some* reading through the
windings, they shouldn't read NO resistance at all.
The specifications for my Yamaha FZR1000's stator is 0.16 to 0.18 ohms.
For an FZR600, the specification is 0.31 to 0.37 ohms. Those are very
small resistances, but at least they show the stator isn't shorted if
you read some low resistance.
I actually measured the resistance on my GS-1100 once, thinking there
might be a problem and got 3 ohms on any output lead to any other
output lead. That might have included test lead resistance, I don't
remember for sure. All the diodes were 15 ohms. My charging problem
turned out to be bad electrical connections. That bad connection inside
the headlight shell really tricked me.
Before I would plunk down $275 for another stator unit, I would wait to
see what the repair manual you ordered says about the resistance. Be
sure you're on the correct setting, R X 1 and zero out the lead
resistance, if that's possible on your multimeter.
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