Balmar Alternator / Regulator Problems

[a64pilot]

I have no idea about a Balmar, but the average automotive alternator is good for about 18,000 RPM, so assuming a 3 to 1 ratio, it’s good for 6000 engine RPM.
Our Marine engines run similar ratios as the automotive guys due largely to space available and ease of construction.
What’s different that in the automotive world is that we try to pull much more power for much longer than in an automobile and we do so at much lower alternator RPM.
What that means is we produce much more heat than an automotive alternator for two reasons, first at a lower speed the field current had to be higher to produce the same power at low RPM, and secondarily and likely more relevant we turn the fans at much lower speed which of course moves less air and less cooling.
I’d like to turn my alternator at 10,000 RPM at Cruise speed, but I don’t think it’s possible with just two pulleys, I think it would take a jackshaft and a second set of pulleys to get the speed high enough.

Remember we aren’t using alternators for what they were designed to do, they were designed to provide power to run the vehicle, not to run the vehicle and charge a huge battery bank.
It’s surprising to me that they last as long as they do.

Unless Balmar has a proprietary alternator and I don’t think the do, I think it’s a highly modified automotive alternator and if it is, it’s just not possible I don’t believe to even come close to overspeeding one with the average sailboat motor and set up.
Now maybe with a custom alternator drive? I believe that Mark Grasser was or is producing some to significantly speed up alternators, but I’ve never seen one.

[CharlieJ]

a64Pilot: "possibility"; given no actionable information I threw the "possibility" out there, but thanks for the the treatise on alternator operation on boats.

[rgleason]

A64 wrote:

Our Marine engines run similar ratios as the automotive... What’s different is that .. we try to pull much more power for much longer ...and we do so at much lower alternator RPM.
... we produce much more heat than an automotive

1. at a lower speed the field current had to be higher to produce the same power at low RPM
2. we turn the fans at much lower speed which of course moves less air and less cooling.
I’d like to turn my alternator at 10,000 RPM at Cruise speed, but I don’t think it’s possible with just two pulleys, I think it would take a jackshaft and a second set of pulleys to get the speed high enough.

I agree with this. Perhaps there is room for a jackshaft with 2"dia and 4" dia" located between the crankshaft pulley and the alternator pulley.
1. Mount a 5.5" serpentine on the front of the existing crankshaft pulley.
2. Serpentine belt between Crankshaft 5.5"dia and 2"dia jackshaft.
3. Serpentine belt behind, between 4"dia jackshaft pulley and alt 2"dia
4. Jackshaft is mounted like an idler pulley or so that the belt tensions can be easily adjusted.

5.5/2.0 = 2.75:1 ratio
4.0/2.0 = 2.00:1 ratio
Total ratio 5.50:1 ratio

Eng RPM Alt RPM
500 2750
1000 5500
1500 8250
2000 11000
2500 13750

I have a sketch I could post. Don't know if this could be done or where to find the parts.

[a64pilot]

I think Mark Grasser built something. I assume it was too expensive for it to be successful.
I mean look at what serpentine “kits” cost that are nothing but three aluminum pulleys and a belt.

What would be interesting would be to know what would the continuous power output difference be if operated in say a 100f compartment?
My 165 amp alt I can only get a continuous 90 amp of continuous power output at a temp that I’m happy with, which is admittedly pretty conservative, I could run it hotter but with what they cost, I’ll stay conservative.

My belief is that even the 200 amp alternators as they are the same case, the same mass and have the same cooling fans may not make all that much more power than a smaller rated alt, when operated continuously. Or I believe they are the same fans etc.
I define continuous being the point at which temps stabilize.

[wsmurdoch]

Originally Posted by WolfgangSeaLife

What would happen if I exceed the max speed?

From https://www.hotrod.com/articles/0206...ur-alternator/

There are several concerns associated with over-spinning an alternator. The steel fingers of the alternator’s rotor can spread as a result of the centrifugal force and actually come in contact with the stationary parts in the alternator. This can cause additional heat and could potentially lock up the alternator altogether. The brushes that ride on the rotor’s copper slip rings and transfer the electrical current to the rotor can begin to bounce at excessively high speeds. This can result in a decrease in alternator capability. Another casualty of over-spinning an alternator can be fan fatigue. This occurs when the centrifugal forces and excessive air pressures flex an alternator’s fan. These distortions can decrease the cooling effectiveness of the fan or even cause it to flex enough to contact the drivebelt. If contact between the belt and fan occurs, the fan and/or belt may be damaged.

[smac999]

Originally Posted by WolfgangSeaLife

I have the Balmar Max Charge 110 V, with MC 614 regulator, just worked fine, until i ran aground and ran the engine to 3100 RPM several times, not overheating, and now it shows no V output. Can there be a connection between running the engine so high and causing an alternator problem?
I have a serpentine belt and pully, which is OK.
Wolfgang

Why would you reply to an 8 year old thread with a new question? Instead of starting a new thread.

[rgleason]

Here is the sketch. I guess the ratios would have to be adjusted to hit 10000 rpm at cruise speed.


wsmurdock, good picture and setup here
http://www.cruisersforum.com/forums/...ml#post2579905
Aren't the bearings, brushes and rotor, in short the entire alternator designed for 10k rpm?

[wsmurdoch]

Could one build an alternator pulley with a planetary gear set enclosed within the body of the pulley so that the drive belt turns the ring gear, the carrier is held motionless, and the sun gear turns the alternator shaft? If the ring gear had 60 teeth and the sun gear 20 teeth, a 3:1 ratio would be generated within the planetary gear set allowing the alternator pulley to be a larger in diameter giving a larger belt contact surface.

Bill

[rgleason]

i ran aground and ran the engine to 3100 RPM several times, not overheating, and now it shows no V output.

I would check your engine mounts and all your alternator connections. Suggest you make a new thread if it is not something simple.

[rgleason]

Originally Posted by wsmurdoch

Could one build an alternator pulley with a planetary gear set enclosed within the body of the pulley so that the drive belt turns the ring gear, the carrier is held motionless, and the sun gear turns the alternator shaft? If the ring gear had 60 teeth and the sun gear 20 teeth, a 3:1 ratio would be generated within the planetary gear set allowing the alternator pulley to be a larger in diameter giving a larger belt contact surface.

Bill

Nice idea, so this would be mounted directly to the alternator in lieu of the pulley, and it would have a means to secure the carrier so it is stationary?


I am still trying to visualize this, but the drive belt would turn the ring gear which could be about 5" dia or about 1:1 ratio so there would be fewer loads on the belt. The ring gear would be offset from the alternator shaft so that the sun gear could be centered on the alternator shaft.


I am going to try to draw this idea. It seems to me that the marine alternator manufacturers could make this bolt on improvement available.

[rgleason]

It seems to me that you could bench test an alternator at various rpm (1000 -15000rpm) in a controlled heat box, that would simulate normal engine room ventilation, at steady state conditions and record alt rpm, alt output, box temperature, etc. to determine if a faster running alternator is more efficient and less heat.

I wonder if such a test has been done? Also why not standardize this test and ask manufacturers to provide the data?

[Cat36Mahalo]

Better check the specs on the alternator you actually have my Prestolite is rated to 8000 Max and factory moto was spinning 7,500 at max engine speed

[rom]

Originally Posted by a64pilot

I have no idea about a Balmar, but the average automotive alternator is good for about 18,000 RPM, so assuming a 3 to 1 ratio, it’s good for 6000 engine RPM.

My Delco 28SI 200A is rated 10000RPM continuous, 12000 intermittent. Reaches max output at about 4500RPM. Ratio is 2.4 which I believe is average in our world. This brings the alt between 5 to 6000RPM at cruising speed, 7500RPM at full throttle.

[Q Xopa]

Originally Posted by rgleason

It seems to me that you could bench test an alternator at various rpm (1000 -15000rpm) in a controlled heat box, that would simulate normal engine room ventilation, at steady state conditions and record alt rpm, alt output, box temperature, etc. to determine if a faster running alternator is more efficient and less heat.

I wonder if such a test has been done? Also why not standardize this test and ask manufacturers to provide the data?

Manufacturers usually do provide a graph to that effect. The typical output curve is more efficient at lower RPMs.
So their max efficiency is at the lower RPM range. Efficiency drops with increase in RPM. It is not linear, efficiency drops very rapidly towards the top 1/3rd of the RPM range.
Im not by my computer just now but if you cant find one I will attach one later.
Obviously the output is less, and the cooling airflow from the fan is also less.

[rgleason]

Originally Posted by Q Xopa

Manufacturers usually do provide a graph to that effect. The typical output curve is more efficient at lower RPMs.
So their max efficiency is at the lower RPM range. Efficiency drops with increase in RPM. It is not linear, efficiency drops very rapidly towards the top 1/3rd of the RPM range.
Obviously the output is less, and the cooling airflow from the fan is also less.

Manufacturers like Balmar provide a "hot" rpm/amps curve and a "cold" rmp/amps curve. Neither of these are for continuous duty at various "box" operating temperatures. Cooling and heat gain information would be very useful at various rpm.


Indeed the typical rpm/output amps curve is initially steep and then levels out. However these are not modeling typical engine room conditions.