Re: nighthawk 550 electrical problem
- From: "krusty kritter" <kriyamanna@xxxxxxx>
- Date: 23 Sep 2005 08:53:50 -0700
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.
.
- References:
- nighthawk 550 electrical problem
- From: jlpridge
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