Balmar Alternator Calibration

[jsalley]

I just replaced the stock Hitachi 60 amp alternator on my Yanmar 3YM20 (Catalina 309) with a 14-pole Balmar 7-series 110 amp alternator. The tach readings appear to be different. The pulley on both alternators is the same. I have not been able to find out the number of poles in the original Hitachi alternator, and suspect the tachometer needs to be calibrated to the new unit, which must have a different number of poles. Does anyone know the number of poles in the Hitachi alternators? How about which setting (A - E) on the back of the tachometer (the factory setting for the Hitachi alternator is C)?

 

[Dan H]

How about try them all until you find the one that tells you what you want it to?
Seriously, use a hand held tach and try them all. Nothing will happen except you'll eventually find the right one.
We used to set the tachs high on the steel mill manipulators so the workers would think they were over revving the engines and really getting it done. Little did they know they were under by about 200 rpm.

 

[jsalley]

How about try them all until you find the one that tells you what you want it to?
Seriously, use a hand held tach and try them all. Nothing will happen except you'll eventually find the right one.
We used to set the tachs high on the steel mill manipulators so the workers would think they were over revving the engines and really getting it done. Little did they know they were under by about 200 rpm.

Thanks - that was my last resort. I was trying to avoid buying another seldom-used piece of test equipment. I'd still need the external tach to try all of the settings.

 

[Maine Sail]

Thanks - that was my last resort. I was trying to avoid buying another seldom-used piece of test equipment. I'd still need the external tach to try all of the settings.

These days you can buy a photo tach for as little as $30.00. That's about 20 minutes of labor from the boat yard...

Amazon Photo Tach

 

[John T1594]

Here is an old and cheap method that I have not seen posted lately.
Place strip of white tape near the outer edge of the face of the crankshaft pulley. Shine a shore powered (60 cycle AC) fluorescent lamp on the pulley with engine running. At 1,800 RPM you should see four steady, stable tape marks hovering at 90 degrees from each other. Adjust Tach. At 3,600 RPM there will be two steady marks hovering at 180 degrees from each other.

 

[Ross]

Does an inverter also run at 60 cycles(hertz)?

 

[jsalley]

Thanks to all. I'd seen the flourescent-light technique described on another forum, but a couple of people who tried it couldn't get it to work. I just ordered the handheld tach from the link posted by Maine.

 

[Tom Metzger]

I've used a flourescent light to set up a tach, and it works well.

As long as the laws of physics aren't repealed it should be OK.

 

[John T1594]

I have used the flourescent light technique several times and it really works. Needless to say that you have to be in a somewhat darkened cabin so you can see the light. It has to be held within a foot or two of the engine pulley so watch out for the belts and other moving parts.

I checked the spec sheet for a small inverter that I have for our TV/DVD player and it says that the output is 60 cycle AC.

 

[ope]

Yanmar tacho calibration

The rpm-meter is made by VDO. You can find installation manual including calibration procedure at:

http://www.vdo.com/downloads/