Ventrac HG150 Generator Question

[John Joseph McVeigh]

I have a question about the Ventrac Model HG150 electrical generator when driven by the Model 4500Y tractor.

The short version: How many kW of electrical power are available at the HG150's output when driven by the 4500Y?

The much longer version:

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In anticipation of the arrival of my Ventrac 4500Y tractor and HG150 Generator, I am trying to determine which electrical loads within my home I will be able to power via a suitable transfer switch and possibly a third circuit-breaker panel fed via the transfer switch. I want to run essential loads such as well pumps (2), oil furnaces (2), a refrigerator, and some lighting. I am also interested in being able to deliver power to some other loads (an internet modem, and one or more computers, all of which are buffered by Uninterruptible Power Supplies, and possibly an electric [induction] cooktop, as natural-gas service is not available here. (Propane is available, of course, but I'd prefer not to use propane.)

What loads I will be able to power will depend, of course, on the output available from the generator. The latter will depend upon the horsepower rating of the tractor's motor, the efficiency of the PTO, and the efficiency of the generator.

From the Ventrac web site, I have downloaded the Owner's Manual for the 4500Y and the HG150, and also the Owner's Manual for the Voltmaster Aeries AB, AR, and EC Two-Bearing Generators. I downloaded these to become familiar with them, and to see if there was a listing for the overall conversion efficiency, or the individual efficiences.

I'm not sure which model of Voltmaster generator the HG150 employs. Unless I have overlooked something, I do not not see a precise specification in the HG150 owner's manual. I suspect it is of the type AR, but the only model of the type AR listed at the Voltmaster web site, the AR100, has power ratings that do not match those of the HG150. The AR100 has ratings that are about one-third less (10 kW peak, 9.5 kW continuous for the AR100 vs. 15 kW peak, 12.5 kW continuous for the HG150).

According to p. 4 of the Voltmaster Owner's Manual available via the Ventrac web site, the AR100 requires 18 HP of mechanical driving power to achieve its rated output (again, 10 kW peak, 9.5 kW continuous). I suspect that the available PTO output of the Model 4500Y is in that ballpark.

If so, and if the conversion efficiency of the HG150 is the same as that of the Voltmaster AR100, then the Model HG150 would seemingly be unable to achieve its rated output power (15 kW peak, 12.5 kW continuous) when driven by the Model 4500Y. If that is the case, it's not the End of the World As We Know It. It's simply a matter of me determining how many "convenience" loads I will be able to power, and moving the appropriate circuits to a third circuit-breaker panel.

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Thanks in advance for any insights.

 

[Raw Dodge]

Unless you have some unusually loads that generator will run your entire house easily,minus an electic range,and electic dryer,both of which you could use if careful.i run my entire house off a northern tool 10k rated 8500 watt continous generator,it easily runs everything and I have. A duplex with a large 3/4 hp well pump,it draws 16 amps to start and 6 once running....I would get a disconnect switch installed between your meter pan and panel,and run the entire main panel with the generator,use a voltmeter and ammeter to verify your loads are balanced closely from leg to leg when using the things you want...I'm telling you,you don't need to leave anything off just don't use the dryer if it's electric and only 1 or 2 burners on the range.your lights especially CFLs and modem are nothing.

 

[John Joseph McVeigh]

Unless you have some unusual loads, that generator will run your entire house easily, minus an electic range, and electic dryer,b oth of which you could use if careful. I run my entire house off a northern tool 10k rated 8500 watt continous generator,it easily runs everything and I have. A duplex with a large 3/4 hp well pump,it draws 16 amps to start and 6 once running....I would get a disconnect switch installed between your meter pan and panel, and run the entire main panel with the generator, use a voltmeter and ammeter to verify your loads are balanced closely from leg to leg when using the things you want...I'm telling you, you don't need to leave anything off, just don't use the dryer if it's electric and only 1 or 2 burners on the range. your lights especially CFLs and modem are nothing.

Thank you for your insights, RD. I do intend to balance the loads across the two halves of the split phase as closely as I can. My thinking behind using a third circuit breaker is to make the transition foolproof. Otherwise, I will need to color-code the breakers on the existing panels to distinguish those which can be closed when the generator is to power the house and those which should be opened, e.g., the electric clothes dryer, the electric oven, and perhaps also the electric hot-water heater. That is certainly doable, and if one is using a flashlight or oil lamp, and paying attention to the color coding, one could keep the overall load on the generator to within acceptable limits.

And yes, the "convenience" loads would draw relatively little power. Some of the lighting is incandescent, and if I turned all of the lights on, there would be a few kW of consumption, but we have been replacing many of the bulbs with CFLs or LEDs as the incandescents have burned out. There are some circuits that have dimmers on them. Some LED bulbs do not like to work with dimmers. The same is true of most CFLs. Those circuits may stay with incandescent loads for a while, as I like to be able to vary the light level in those locations.

 

[John Joseph McVeigh]

In partial answer to my own question, I see, in the Specifications section of the HG150 brochure available for download at the Ventrac web site, the following:

"Minimum Require[d] Engine HP[:] 16."

It's unclear whether that is the minimum HP required to achieve the rated output of 12,500 watts peak, 10,000 watts continuous.

One horsepower equals 745.7 watts. So, 12,500 watts equals 16.8 mechanical horsepower, and 10,000 watts equals 13.4 mechanical horsepower. Here is where the conversion efficiencies of the generator and of the PTO hydraulics come into play.

No generator is perfectly efficient in converting mechanical power into electrical power. There will be some resistive losses in the wire that makes up the coils of the generator and some hysteresis and eddy-current losses in the pole-pieces on which the coils are wound. There will be at least some frictional losses in the bearings.

If the generator is, say, 75% efficient (which I believe is a very high number in this context), then one would need to apply 22.4 mechanical horsepower to the input shaft for the generator to achieve 12,500 watts of electrical output power.

There will also be some mechanical losses in the drive belt and in the PTO hydraulics. Those will be at least a few hp.

I suspect that the HG150 will be unable to achieve its rated peak output power when driven by the Model 4500Y. The Model 4500Z, however, might have enough engine power to do it. That said, I am content with the rated power of the Model 4500Y. It should be well suited to my tasks.

On SCUTs with diesel motors similar in size to that in the Model 4500Y, e.g., the Massey Ferguson GC1705, the rated engine crankshaft power is 24 hp, and the rated PTO power is 19 hp.

Again, it's not a big deal to me that I might "only" be able to get, say, 8,000 or 9,000 watts out of the HG150. That will be more than enough to run the essential electrical loads and quite a few "convenience" loads. I'm simply trying to work out a power budget and to see how many "convenience" loads I will be able to feed.

 

[Raw Dodge]

I just bought these from home depot in a 6 pack for 58.00 shipped to my door.Let me tell you they are awesome, I'm going to buy more when funds allow..they are bright, and very warm color, and I was skeptical about there dimming performance but they dim down great..only issue is they don't get dim down to the point of barely lit like an incandescent, but I think that's more a function of the resistor in the switch because the amperage on that circuit has been but cut from1.5 amps down to about 1/3 an amp.. they are so bright I think it would take a 100 watt incandescent to match their output. They blow away the cfls i have everywhere i dont need a dimmer.

 

[John Joseph McVeigh]

In partial answer to my own question, I see, in the Specifications section of the HG150 brochure available for download at the Ventrac web site, the following:

"Minimum Require[d] Engine HP[:] 16."

It's unclear whether that is the minimum HP required to achieve the rated output of 12,500 watts peak, 10,000 watts continuous.

One horsepower equals 745.7 watts. So, 12,500 watts equals 16.8 mechanical horsepower, and 10,000 watts equals 13.4 mechanical horsepower. Here is where the conversion efficiencies of the generator and of the PTO hydraulics come into play.

No generator is perfectly efficient in converting mechanical power into electrical power. There will be some resistive losses in the wire that makes up the coils of the generator and some hysteresis and eddy-current losses in the pole-pieces on which the coils are wound. There will be at least some frictional losses in the bearings.

If the generator is, say, 75% efficient (which I believe is a very high number in this context), then one would need to apply 22.4 mechanical horsepower to the input shaft for the generator to achieve 12,500 watts of electrical output power.

There will also be some mechanical losses in the drive belt and in the PTO hydraulics. Those will be at least a few hp. [....]

I should rephrase part of the above.

It is clear: 16 hp of engine crankshaft power is not enough to drive the HG150 to its rated peak output output of 12,500 Watts. 12,500 watts equals 16.8 mechanical horsepower. Obtaining 16.8 hp of output power from 16.0 hp of input power would violate the first law of thermodynamics, if not also the second law. Obtaining 13.4 hp (10,000 Watts) of output power from 16.0 hp of input power would violate neither the first nor the second law of thermodynamics, but it would require a throughput (diesel-motor-crankshaft-to-electrical-output-socket) efficiency of 83.75%, which seems very high.

 

[John Joseph McVeigh]

I just bought these from home depot in a 6 pack for 58.00 shipped to my door.Let me tell you they are awesome, I'm going to buy more when funds allow..they are bright, and very warm color, and I was skeptical about there dimming performance but they dim down great..only issue is they don't get dim down to the point of barely lit like an incandescent, but I think that's more a function of the resistor in the switch because the amperage on that circuit has been but cut from1.5 amps down to about 1/3 an amp.. they are so bright I think it would take a 100 watt incandescent to match their output. They blow away the cfls i have everywhere i dont need a dimmer.

View attachment 403143

Thanks for bringing those to my attention, RD. LEDs are clearly the wave of the future. CFLs are a transitional technology. They have their uses, but LEDs are more suitable in applications in which CFLs are problematic, e.g., in outdoor fixtures and in poorly insulated indoor fixtures. During Winter months, CFLs in cool places can have problems starting up, and they can take a bit of time to get up to their rated light output, if they ever get there at all. LEDs will start right up without balking, even in very cold temperatures.

 

[JackIL]

1. There is another consideration on power. The advertised peak tractor power is based on an engine speed of 3600 rpm, but the engine speed at which the generator frequency is correct for household current will be somewhere between 3,000 and 3,200 rpm according to the Operators Manual.

2. I have successfully used a Steiner generator (10 KW peak) on a Ventrac for many years to power my home in emergencies both summer and winter. There is a transfer switch that connects the generator into the main power line to the house ahead of the breaker panel so individual circuits are not selected. We just judiciously limit the use of appliances and lights so that the power demand is not excessive. We do not shut off the air conditioner. No difficulties have arisen in this mode of operation.

The most demanding use occurred in 2008 when a derecho took down a lot of trees that fell across power lines. The main power line to our house was out for over 5 days. The tractor and generator ran for 119 straight hours to provide electical service and was only stopped to refill the fuel tank as needed and change engine oil twice. The most noticeable power demand was turning on the microwave oven--the engine speed droop was easily heard. Otherwise the tractor just hummed along. This was a 31 hp Turbo Diesel.

 

[John Joseph McVeigh]

1. There is another consideration on power. The advertised peak tractor power is based on an engine speed of 3600 rpm, but the engine speed at which the generator frequency is correct for household current will be somewhere between 3,000 and 3,200 rpm according to the Operators Manual.

2. I have successfully used a Steiner generator (10 KW peak) on a Ventrac for many years to power my home in emergencies both summer and winter. There is a transfer switch that connects the generator into the main power line to the house ahead of the breaker panel so individual circuits are not selected. We just judiciously limit the use of appliances and lights so that the power demand is not excessive. We do not shut off the air conditioner. No difficulties have arisen in this mode of operation.

The most demanding use occurred in 2008 when a derecho took down a lot of trees that fell across power lines. The main power line to our house was out for over 5 days. The tractor and generator ran for 119 straight hours to provide electical service and was only stopped to refill the fuel tank as needed and change engine oil twice. The most noticeable power demand was turning on the microwave oven--the engine speed droop was easily heard. Otherwise the tractor just hummed along. This was a 31 hp Turbo Diesel.

Thank you for your observations, Jack.

That is a good point about the difference between crankshaft rpm for rated crankshaft hp and crankshaft rpm for a 60-Hz generator output frequency. Do you use a frequency counter to set the output frequency to 60 Hz? Or do you adjust the crankshaft rpm solely to keep the generator's output voltage within spec?

The Derecho of June 29, 2012 caused us (and many others) to lose power. I will have to check my records to make sure, but I think that the utility restored service within three days. Considering how many people lost power, I was surprised that the utility was able to restore power to us so quickly. But other Marylanders were out of power for more than one week. As I recall, some Pennsylvanians were without power for upwards of 10 to 14 days.

The owner's manual for the Model 4500Y specifies that the motor oil should be changed after the first 50 hours, after the first 100 hours, and thence at 100-hour intervals (unless the unit will be stored for four months or more). There is a notation to consult the Engine Owner's Manual (which I do not yet have) as to oil-change intervals for heavy loads and high temperatures, and another notation that, if the Engine Owner's Manual does not have a recommendation for oil changes related to operation under heavy loads, at high temperatures, or in dusty conditions, then Ventrac recommends oil changes at half the regular intervals (i.e., in the case of the 4500Y and 4500Z, every 50 hours). Do you consider operation of the generator for extended periods to be operations under heavy load, and thus grounds for more frequent oil changes?

 

[JackIL]

I routinely follow the Ventrac recommended oil change intervals. That is why I had to do 2 in the 119 hour event. The first was due soon after the event started and the second 100 hours later. I did not think the work load with the generator to be "heavy," so I did not go to more frequent intervals.