Alternator Adaption from Kawasaki to B&S

B

bartles

Well-Known Member
I'm rebuilding a Gravely ZT50. It has a B&S model 407577-0292-E1 that the previous owner chose to replace the
the "as shipped" Kawasaki. As I look at the different alternators available I am unable to determine what one I have(black and red wire).

I'd appreciate advice on what amp rating I would need. The mower wiring harness has a three-wire connector: regulator, fuel solenoid, magneto kill.


Thanks in advance,

bartles
 
Red Wire will have lump [diode] in it.

It a dual with Red +12 vdc unregulated 3 amp and Black wire being AC at 5 amps.

IF you have an electric PTO you need to upgrade the stator to at least a tri-circuit 5-9 amp depending on the flywheel magnets and add a voltage regulator.
 
Thanks! It does have an electric PTO. Is it just me or does everyone have difficultly reading in the B&S website what is available in the way of alternators and regulators.... I can not read what is on that page.

I appreciate the help,

bartles
 
My advice would be to remove the flywheel and update the charging stator and put a 3-wire B&S regulator on this engine.

Of course, that will depend on if the B&S flywheel has a full complement of stator magnets.

If not, I suspect the stator amperage output will be too low for long period of use. That means the PTO clutch will overheat and melt down the field pull-in windings.
 
Auto Doc's said:
My advice would be to remove the flywheel and update the charging stator and put a 3-wire B&S regulator on this engine.

Of course, that will depend on if the B&S flywheel has a full complement of stator magnets.

If not, I suspect the stator amperage output will be too low for long period of use. That means the PTO clutch will overheat and melt down the field pull-in windings.
Click to expand...
Thanks for the information......re flywheel magnets....really dumb question...I am assuming by the number of flywheel magnets the new alternator needs to match the number of magnets in th flywheel.

In the B&S website, there is only one flywheel offered for my model number, but three alternators offered, so I am assuming they all would work with these alternators...safe assumption?
 
bartles said:
Thanks for the information......re flywheel magnets....really dumb question...I am assuming by the number of flywheel magnets the new alternator needs to match the number of magnets in th flywheel.

In the B&S website, there is only one flywheel offered for my model number, but three alternators offered, so I am assuming they all would work with these alternators...safe assumption?
Click to expand...
No worries,

Here is a brief operational description to help you understand better:

The flywheel has magnets attached to the underside, with "alternating" North and South poles of polarity. When the engine is running, these magnets rotate rapidly past the (stationary) stator winding, and it produces an "alternating current" (AC) of approximately 25-30 volts.

The voltage regulator is fed the AC current, and it "rectifies" it too approx. 13.5 volts "direct current" (DC).

The difference in charging systems comes with how the rider manufacturer designs the machine. If it has lights and an electric PTO it requires the higher amperage stator/alternator to operate everything and still be able to recharge the battery efficiently.

You need the highest output stator/alternator and a 3-wire external voltage regulator. The voltage regulator has to be grounded/bolted to the engine and the single red wire lead connected to the battery positive. The two-yellow wire connector attaches to the stator/alternator lead.

(Very important) Charging voltage must be checked at the battery when running with all wires connected. The voltage regulator will not operate if only the red lead is checked while disconnected.

Always test charging voltage at idle then at full throttle to make sure the battery is getting charged above 12.6 volts DC.
 
Auto Doc's said:
No worries,

Here is a brief operational description to help you understand better:

The flywheel has magnets attached to the underside, with "alternating" North and South poles of polarity. When the engine is running, these magnets rotate rapidly past the (stationary) stator winding, and it produces an "alternating current" (AC) of approximately 25-30 volts.

The voltage regulator is fed the AC current, and it "rectifies" it too approx. 13.5 volts "direct current" (DC).

The difference in charging systems comes with how the rider manufacturer designs the machine. If it has lights and an electric PTO it requires the higher amperage stator/alternator to operate everything and still be able to recharge the battery efficiently.

You need the highest output stator/alternator and a 3-wire external voltage regulator. The voltage regulator has to be grounded/bolted to the engine and the single red wire lead connected to the battery positive. The two-yellow wire connector attaches to the stator/alternator lead.

(Very important) Charging voltage must be checked at the battery when running with all wires connected. The voltage regulator will not operate if only the red lead is checked while disconnected.

Always test charging voltage at idle then at full throttle to make sure the battery is getting charged above 12.6 volts DC.
Click to expand...
Hey I appreciate this info!

Regards,

bartles
 
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