Portable Generator Question

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6 gauge wire is to large to fit in my current bus bar. Has anyone ever used one of these adapters?
 

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Tip DS said:
Ah, the good old suicide cord. Not that code matters, but NFPA 70, section 406.7(B) states, "Connection of Attachment Plugs. Attachment plugs shall be installed so that their prongs, blades, or pins are not energized unless inserted into an energized receptacle or cord connectors. No receptacle shall be installed so as to require the insertion of an energized attachment plug as its source of supply." So, I guess TECHNICALLY that's a code infraction.
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It's a code violation to use it.
Not make it.
 
Tip DS said:
Yeah, I don't think we are arguing about that. TBH, I've made AND used them. So, I'm covered as far as code infractions are concerned. :ROFLMAO:
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I've done the generator input without an interlock trick until I did what I said I'd never do.(turned utility on before turning off
generator input breaker)
Fortunately I got it turned back off before utility power destroyed the generator.
 
I have a Kohler 7.5c61 kind of like the one in this picture. It just barked loud and the lights dimmed a bit when my 2.5 ton air conditioner started. It's got lots of rotating mass, but it only turns 1800 so not sure how much energy is stored. The voltage dip, and maybe frequency dip wasn't enough to set off my Triplite 1500 UPS.

441883-ee428f772a4618cdb15d80fe7ffbb176.jpg
 
Tip DS said:
... I'm not an HVAC guy, but couldn't that be addressed with a large starting capacitor?
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No.

A larger start capacitor is generally part of a "hard-start" kit. They're a useful kludge when something else is wrong with the system -- worn-out compressor, short cycling, nonfunctional pressure equilization, et al. But they function by drawing more starting current, and thus yielding more torque from the compressor motor's start winding.

Hard-start kits are only usable when hooked up to a power source with an abundance of current available. For use with a portable generator without sufficient current capacity, a soft-start kit is needed. (after assuring that there aren't any mechanical or thermodynamic problems)


Tip DS said:
Yeah, they make cyanide, too. I'm sure not running out to use that! :p
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Cyanide is hazardous, but has a lot of legitimate uses. A suicide cord does not.
 
Joethemechanic said:
Yeah I have run my 2.5 ton at my old house on an 8kw. But the lights dimmed a bit when the compressor started. And you could see the governor take the throttle wide open foe a few seconds
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See you did have some volts/frequency drop even with a larger unit later in the thread. It takes a pretty good size genset to be able to ride through a motor starting without dropping volts/frequency even if only very briefly.
 
drcampbell said:
Cyanide is hazardous, but has a lot of legitimate uses.
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When I was in middle school we used cyanide for case hardening our metal shop projects. I think we were in 7th grade. Teacher told us not to breathe the fumes so we held our breath when sticking the glowing steel into the cyanide.
 
kwired said:
See you did have some volts/frequency drop even with a larger unit later in the thread. It takes a pretty good size genset to be able to ride through a motor starting without dropping volts/frequency even if only very briefly.
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No, it's always been the Kohler 7.5c61 It's rated 7.5 KW but I sometimes round up. It's from back in the day, and I think they rated them a bit more conservatively then. I loaded it down with 9KW resistive load and it was holding it, and there was still a little throttle to go. During Hurricane Sandy that thing powered my whole house for over a week (not AC or dryer) and two of my neighbors had 120v cords plugged in for lights and refrigerator

Even though it's a good little unit, It doesn't start heavy loads like an infinite buss.
 
Joethemechanic said:
No, it's always been the Kohler 7.5c61 It's rated 7.5 KW but I sometimes round up. It's from back in the day, and I think they rated them a bit more conservatively then. I loaded it down with 9KW resistive load and it was holding it, and there was still a little throttle to go. During Hurricane Sandy that thing powered my whole house for over a week (not AC or dryer) and two of my neighbors had 120v cords plugged in for lights and refrigerator

Even though it's a good little unit, It doesn't start heavy loads like an infinite buss.
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utility isn't infinite bus, but is usually more stout than a generator on site will be. Utilities have smaller transformers than what we would typically install as a separately derived system to supply same load. They also often have smaller conductors and sometimes somewhat long distances with those small conductors. Voltage still drops, frequency however doesn't change like it will with a local generator when sudden load change occurs.
 
kwired said:
utility isn't infinite bus, but is usually more stout than a generator on site will be. Utilities have smaller transformers than what we would typically install as a separately derived system to supply same load. They also often have smaller conductors and sometimes somewhat long distances with those small conductors. Voltage still drops, frequency however doesn't change like it will with a local generator when sudden load change occurs.
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Yeah I guess not infinite bus. Really the entire grid isn't infinite. They have a lot of good reasons for smaller transformers like improving lagging power factor, limiting incident energy, and really most services almost never get close to their rated amperage. And if they do, the duration is very brief.

Our summer home up in Tioga County had a 60 amp service and the pole in our yard only had a 5kva pot on it
 
kwired said:
You are on the right track here. Generator will almost always have more voltage sag when starting motor loads than when starting on utility power. This will have somewhat of a soft starter (reduced voltage starting) effect on the motor you are trying to start as well. Keep in mind it will not accelerate as fast as when starting on utility power either.

Other considerations is how much load is already running when attempting to start that AC compressor.

I have a 8000 watt portable generator, haven't had to try to start my 3 ton heat pump with it for several years now. But it will run my 3 ton heat pump. Has difficulty starting before it blows the 30 amp generator breaker if there is much other load running already when you try to start it. But once it is started that heat pump often only draws 6 to maybe 8 amps and there is capacity to run other loads once the heat pump is started.
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Would there be any possibility of damaging my HVAC unit by only supplying it only 80% of its required start up power requirements? Another concern for me is running my refrigerator, and freezer at the same time, and having the HVAC unit stop, and restart as it gets up to set thermostat temperature.
 
Esay said:
Would there be any possibility of damaging my HVAC unit by only supplying it only 80% of its required start up power requirements? Another concern for me is running my refrigerator, and freezer at the same time, and having the HVAC unit stop, and restart as it gets up to set thermostat temperature.
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Have you bought the generator yet? Is there a specific model?
 
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I wouldn't spend lots of money oversizing the generator to run the heat pump without at least looking at the cost of an inverter heat pump that doesn't have significant starting current requirements.

-Jon
 
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