Gen sets MEP need advice

[nextalcupfan]

Just going to throw my $.02 in here. According to the spec sheet Coug put up that HVAC unit has Soft-Start capability, that means startup surge should be almost non-existent. (Emphasis on should)
According to your first post all your other loads will be "tv, laptops, cell phones, radios and chargers".
Unless you have some monster high powered transmission radio (like a CB with a 200w kicker) all of those should be able to be powered by the convenience outlet easily.
Depending on the size the TV is probably 50-100w, Laptop chargers 30-75w, Cell Phones 10-30w, Standard FM radio 5-10w, and just "chargers" is far to broad i would need to know exactly what type. However I looked up a DeWalt 20v MAX charger and its input current is 1.5A or 180w.
But if you had 2 of each except the TV everything together is at worst 690w, which is only 5.75A from the convenience outlet, everything but the DeWalt Chargers only came to 330w btw.

If this were me (since I already have one) I would try to run this on an 803a, according to the specs of similar units the heating is done with resistive heat.
That means no surge and 1.0powerfactor.
The MEP803a can put out around 12.25kW on 3ph at 1.0pf, your max heating load is 12.18kW.
That is 99% load and adding in your other electronics that comes to 105% load. Now don't get me wrong thats alot, and if it was continuous I would defiantly suggest an 804x generator.
But you need to keep in mind you're only heating a tent so your run times on the HVAC unit should be quite short. (depending on the insulation value of the tent and the temp difference outside)
So I would wager over 50% of the time your generator is running it would be effectively idling just charging your small devices.
This is going to cause Wet Stacking fairly quickly, which is IMO the number 1 problem with these MEP's.

I would also like to note I've seen Youtube videos (I think from members of this very forum) of loading an 803a to 17kW on 3ph briefly and it handling it like a champ.

As for your concerns on running the unit in 3ph and plugging in 120v devices it's not an issue.
3ph is after all 3 individual 120v legs 120 degrees out of phase with each other. So to get 120v all you need to do is pull off 1 leg and neutral (The convenience outlet is wired to L3 and neutral)

Wow sorry this came out way longer winded than I intended...
Anyway in conclusion I personally think you should get an 803a (IF possible maybe a forum member can let you use one to see if it can handle the load before you buy?)
If you're really concerned about overloading it however just remember if you get an 804x you're going to need some way to burn the wet-stacking out of it. (Honestly you might even wet-stack the 803a a bit if the HVAC unit isnt coming on very often.)

And don't worry about your electronics loads you mentioned, they are a drop in a swimming pool compared to your HVAC load.
Now if you want to add a fridge/microwave/coffee maker thats a whole other story.

 

[nextalcupfan]

Both the 803 and 804 are three phase only. You can still run your single phase equipment on one leg to neutral.

Not quite, the 803 is single and 3 phase selectable 804 is 3 phase only.

 

[peapvp]

I could easily be wrong about the wattage. If you're correct then you want the MEP-804 because of compressor surge current. @peapvp may check in tonight or next couple of days. He's got a strong background on electrical requirements and gen sets. You'll want to run the generator at60 Hz for US equipment. Both the 803 and 804 are three phase only. You can still run your single phase equipment on one leg to neutral.

I'm curious why you need such a big HVAC unit for a tent. May I ask that you describe a little more about your application?

Since @Evvy got me suckered into this,
per manufacturer datasheet, this unit has the following ratings for power consumption:

Power
Voltage (V/Phase/Hz) 208/3/50-60VAC 208/3/50-60VAC
Control voltage 24/1/50-60VAC 24/1/50-60VAC
Max power
Cooling 10,650 Watts 10,650 Watts
Heating 12,180 Watts 12,180 Watts
Compressor soft-start capability Yes Yes
Main onboard power circuit
breaker
50 Amp. 3 Pole 50 Amp. 3 Pole
Power cable length 50' 15.2 m
Power cable connector MS3102R32-17P (4 Pin, 3P-E )

A 15KW would be enough. A 10KW is to small.
They are usually connected to a Load Center, which has connections for 3 Phase and Single Phase outputs.
Either the 804 Alpha or Bravo will work fine. It's really about which one is available at what price.

I think this should answer the question

Peter

 

[Evvy Fesler]

Just going to throw my $.02 in here....

If this were me (since I already have one) ...

And don't worry about your electronics loads you mentioned, they are a drop in a swimming pool compared to your HVAC load.
Now if you want to add a fridge/microwave/coffee maker thats a whole other story.

Ah! So.... there is this concept called scope creep where this year you think you're all set and then you add... another little load, and then another... and another. Next thing you know you want to run a battery charger for your ATV. I love this thread. It's a great example of any project where the first step is to pull your requirements together, then design it, and then purchase the equipment. Way cheaper that way. Do plan for scope creep; especially if you have children. They're famous for expanding needs. :0)

 

[Evvy Fesler]

Since @Evvy got me suckered into this,
per manufacturer datasheet, this unit has the following ratings for power consumption:

Power
Voltage (V/Phase/Hz) 208/3/50-60VAC 208/3/50-60VAC
Control voltage 24/1/50-60VAC 24/1/50-60VAC
Max power
Cooling 10,650 Watts 10,650 Watts
Heating 12,180 Watts 12,180 Watts
Compressor soft-start capability Yes Yes
Main onboard power circuit
breaker
50 Amp. 3 Pole 50 Amp. 3 Pole
Power cable length 50' 15.2 m
Power cable connector MS3102R32-17P (4 Pin, 3P-E )

A 15KW would be enough. A 10KW is to small.
They are usually connected to a Load Center, which has connections for 3 Phase and Single Phase outputs.
Either the 804 Alpha or Bravo will work fine. It's really about which one is available at what price.

I think this should answer the question

Peter

LOL Peter - I knew you'd come through flying colors!

 

[Evvy Fesler]

Not quite, the 803 is single and 3 phase selectable 804 is 3 phase only.

You are so correct!

 

[peapvp]

Just going to throw my $.02 in here. According to the spec sheet Coug put up that HVAC unit has Soft-Start capability, that means startup surge should be almost non-existent. (Emphasis on should)
According to your first post all your other loads will be "tv, laptops, cell phones, radios and chargers".
Unless you have some monster high powered transmission radio (like a CB with a 200w kicker) all of those should be able to be powered by the convenience outlet easily.
Depending on the size the TV is probably 50-100w, Laptop chargers 30-75w, Cell Phones 10-30w, Standard FM radio 5-10w, and just "chargers" is far to broad i would need to know exactly what type. However I looked up a DeWalt 20v MAX charger and its input current is 1.5A or 180w.
But if you had 2 of each except the TV everything together is at worst 690w, which is only 5.75A from the convenience outlet, everything but the DeWalt Chargers only came to 330w btw.

If this were me (since I already have one) I would try to run this on an 803a, according to the specs of similar units the heating is done with resistive heat.
That means no surge and 1.0powerfactor.
The MEP803a can put out around 12.25kW on 3ph at 1.0pf, your max heating load is 12.18kW.
That is 99% load and adding in your other electronics that comes to 105% load. Now don't get me wrong thats alot, and if it was continuous I would defiantly suggest an 804x generator.
But you need to keep in mind you're only heating a tent so your run times on the HVAC unit should be quite short. (depending on the insulation value of the tent and the temp difference outside)
So I would wager over 50% of the time your generator is running it would be effectively idling just charging your small devices.
This is going to cause Wet Stacking fairly quickly, which is IMO the number 1 problem with these MEP's.

I would also like to note I've seen Youtube videos (I think from members of this very forum) of loading an 803a to 17kW on 3ph briefly and it handling it like a champ.

As for your concerns on running the unit in 3ph and plugging in 120v devices it's not an issue.
3ph is after all 3 individual 120v legs 120 degrees out of phase with each other. So to get 120v all you need to do is pull off 1 leg and neutral (The convenience outlet is wired to L3 and neutral)

Wow sorry this came out way longer winded than I intended...
Anyway in conclusion I personally think you should get an 803a (IF possible maybe a forum member can let you use one to see if it can handle the load before you buy?)
If you're really concerned about overloading it however just remember if you get an 804x you're going to need some way to burn the wet-stacking out of it. (Honestly you might even wet-stack the 803a a bit if the HVAC unit isnt coming on very often.)

And don't worry about your electronics loads you mentioned, they are a drop in a swimming pool compared to your HVAC load.
Now if you want to add a fridge/microwave/coffee maker thats a whole other story.

Suum Cuique,
running 02 or 03 beyond the name plate rating because they are de rated is like pulling quarters out of hogs A..
All this extreme loading does is causing excessive wear on bearings and other moveable parts plus the additional heat development.

The 02 and 03 where made for front line combat, hence they can give you some more bang when the bullets, mortars and grandees are flying.......

Peter

 

[nextalcupfan]

Ah! So.... there is this concept called scope creep where this year you think you're all set and then you add... another little load, and then another... and another. Next thing you know you want to run a battery charger for your ATV. I love this thread. It's a great example of any project where the first step is to pull your requirements together, then design it, and then purchase the equipment. Way cheaper that way. Do plan for scope creep; especially if you have children. They're famous for expanding needs. :0)

Yes I totally agree with this statementm my write up is pretty much about your needs right now not possible future loads.
Though I still think your main load would be inconsistent enough that even another 1000w wouldn't really be a problem, just that you couldn't run that off the convenience outlet alone.

 

[nextalcupfan]

Suum Cuique,
running 02 or 03 beyond the name plate rating because they are de rated is like pulling quarters out of hogs A..
All this extreme loading does is causing excessive wear on bearings and other moveable parts plus the additional heat development.

The 02 and 03 where made for front line combat, hence they can give you some more bang when the bullets, mortars and grandees are flying.......

Peter

But according to my calculations we would be pretty much at "nameplate rating" +/- 5%, and as far as I understand these units being "Prime Power" should be able to put out 100% continuously with no issue.

I would also like to mention again the 100% should be very inconsistent from his HVAC unit, probably less than 50% duty cycle. (very rough guess)

 

[peapvp]

But according to my calculations we would be pretty much at "nameplate rating" +/- 5%, and as far as I understand these units being "Prime Power" should be able to put out 100% continuously with no issue.

I would also like to mention again the 100% should be very inconsistent from his HVAC unit, probably less than 50% duty cycle. (very rough guess)

Your 20% over name plate rating when heating:
Heating 12,180 Watts 12,180 Watts
that's the power consumption or load

 

[nextalcupfan]

Your 20% over name plate rating when heating:
Heating 12,180 Watts 12,180 Watts
that's the power consumption or load

The nameplate rating is at 0.8pf though, at 1.0pf its 12,250w. According to what I was able to look up his HVAC uses resistive heating which is 1.0pf. (minus a smidge for the blower fan)
Actually I would be more concerned with the 10,650w in cooling mode because that would have a lower pf, I just don't know how much.

 

[peapvp]

The nameplate rating is at 0.8pf though, at 1.0pf its 12,250w. According to what I was able to look up his HVAC uses resistive heating which is 1.0pf. (minus a smidge for the blower fan)
Actually I would be more concerned with the 10,650w in cooling mode because that would have a lower pf, I just don't know how much.

Congratulations,
You just created a generator head which has no internal resistance. Absolute 0 Ohm coil system........
IBM is still at 77 K (−196.2 °C; −321.1 °F) for superconductor state.

 

[peapvp]

To explain this:

The de rating is applicable only to the engine itself and the shaft horse power / torque output capability.

The engine has to have a higher Horse Power Rating so it can produce the same amount of torque at 5'000 Feet above sea level as what is required to produce the same torque at sea level.

The reason for this is the fact that at higher altitudes the oxygen level in the air drops down significantly

The torque is what makes your KW minus the internal losses (PF) in generator head.

So, at sea level you can overload the genhead without bogging down your engine.......

 

[nextalcupfan]

According to my nameplate generator output is 52A at 240v single phase and 34A at 208v 3 phase.
Wouldn't that come to 12,480w for single and 12,250w for 3ph?

 

[peapvp]

According to my nameplate generator output is 52A at 240v single phase and 34A at 208v 3 phase.
Wouldn't that come to 12,480w for single and 12,250w for 3ph?

That would be correct without the power factor. With Power Factor of 0.8PF the KW for 240V is 9.984 KW so 16 Watt short to 10KW

The power factor applies to the Generator Head and does not magically disappear.

The nameplate current of 52 Amps reflects the allowance to meet peak demands when starting a inductive load before the Circuit Breakers will Trip after some time delay.

Otherwise, the generator should not be operated for a prolonged period of time at anything above 10KW

 

[jsdirtngravel.tyler@gmail]

Did I mention GFCI? Think I did. Just wanted to make sure. Camping can be wet. N’uff said.

Huh? What's GFCI?

 

[peapvp]

Huh? What's GFCI?

I would google it
Ground Fault Circuit Interrupt
Wiki problem got a full run down on it

 

[Coug]

Something also to think about...

So I don't know if your generator is capable of doing this on, but I'm running a 3 ton ECU on a 5kw generator (NordicAir)
The aircon portion works just fine on the 5k.
The heating portion is rated to draw over 9kw.

The heater portion is a bunch of heater elements, wires in parallel, equal number per phase.
I disconnected one element per phase, which brought me down to around 6kw plus blower motor.

Then I use the voltage adjustment knob on the control panel of the generator, and reduce from 208V down to about 200V.
The heater is straight resistive elements, so they don't care what voltage they see. The voltage is still within the operating range for the blower motor, so it also doesn't care.
Load gauge on the control panel reads right about 100%.
I'm also less than 1k feet above sea level.

Not saying you should or even can do this with your ECU, but it might be possible to reduce the number of heater elements being operated to drop the amount of load on the generator.


Below is just something to consider if you plan to use the generator/ECU as a heat source.

I will add to this though, using a diesel generator to produce electric heat is extremely wasteful.
The generator is burning fuel, which produces heat, that is discarded, to create rotational force.
The gen head is taking that rotational force to create electricity, which also produces heat in the process, and that is discarded.
The electricity then goes over to the ECU where it turns the blower motor, producing heat which is usually discarded as the blower motor itself isn't always in the airflow path.

#2 diesel has approximately 137,000 BTUs of energy in it.

Every time you convert from one type of force to another, energy (heat) is produced. Most times that heat is wasted to the surrounding environment.

My MEP-802A burns 1/2 gallon of diesel per hour
My ECU with 1/3 of the heater elements disconnected produces about 21k BTUs of heat per hour.
So per 1 gallon of fuel I enjoy about 42k BTUs of heat.
So you get approximately 31% of the available heat energy from the diesel fuel returned to you as usable heat. With a more efficient generator you might get closer to 40%, maybe even a little above that, but you are still going to waste a lot of energy.


My H45 diesel stove produces 45k BTUs of heat per hour.
Its rated to burn 0.40 gallon of diesel on high per hour.
Some heat is wasted up the chimney, but you're still talking about double the usable heat produced per gallon of diesel fuel.
in 2.5 hours at full burn you'll use 1 gallon of diesel, and produce 112,500 BTUs of heat
You get approximately 82% of the available energy from the diesel fuel burned.

 

[Guyfang]

Below is just something to consider if you plan to use the generator/ECU as a heat source.

I will add to this though, using a diesel generator to produce electric heat is extremely wasteful.
The generator is burning fuel, which produces heat, that is discarded, to create rotational force.
The gen head is taking that rotational force to create electricity, which also produces heat in the process, and that is discarded.
The electricity then goes over to the ECU where it turns the blower motor, producing heat which is usually discarded as the blower motor itself isn't always in the airflow path.


Were you in he Military? Never in a life time, would anyone even think about: I will add to this though, using a diesel generator to produce electric heat is extremely wasteful.

 

[Guyfang]

Huh? What's GFCI?

This is a good question. We all, (me too) sit around using terms that most folks have no idea about.

GFCI, Ground Fault Circuit Interrupter. Indeed, I would look it up, but the short simple story is, "A device that measures how many Amps goes into a circuit, and how many comes back out on the Neutral. When the figures do not match, it cuts the circuit off."

Why? Well if you are standing there with a broken wire in hand, and the voltage is going through you to ground, you are going to maybe die. The GFCI is there to protect your life. I am sure all of you can explain it much better then me. But the question was asked, and telling someone to Google it, is not the answer.