Generator install, sizing, location

   / Generator install, sizing, location #21  
Here are some pictures. The first is the overall control boxes. The upper has the DHW contactor, the mid box has the logic and control and the bottom is the switch and indicators. What is not visible is on the right side of the logic box is the Sonalert (beeper) to indicate that the genset is running and the utility power is also present. The next picture shows the interior of the logic/control box. Below that is a close up of the logic circuit. The next picture shows the interior of the DHW contactor and the last picture is a close up of the controls.

I did not open the main panel to show the utility pick up wire or the small amplifier box associated with the pick up.

paul
 

Attachments

  • Power Control Boxes.JPG
    Power Control Boxes.JPG
    232.5 KB · Views: 103
  • Power Logic.JPG
    Power Logic.JPG
    371.6 KB · Views: 105
  • Logic Board.JPG
    Logic Board.JPG
    347.8 KB · Views: 117
  • Heater Contactor.JPG
    Heater Contactor.JPG
    263 KB · Views: 118
  • DHW Controls.JPG
    DHW Controls.JPG
    220.5 KB · Views: 120
   / Generator install, sizing, location #22  
To give you and idea what a 20kw standby generator will do, we have a 20kw Kohler (LP gas on a 500-gallon dedicated tank) automatic standby generator that was professionally installed and it easily starts and runs a 4-ton high efficiency heat pump with a 40-gallon electric hot water heater running on line at the same time. The only thing the installer added is a relay to prevent the emergency heat strips from cycling on during the heat pump's defrost cycle when on generator power otherwise everything in our 3.000 sq. ft. all electric home is on the generator during a power outage. There have been absolutely no problems with it so far. Utility power goes off and we're on generator power in about 10 seconds. Our power outages have been as long as 50-60 hours.

The generator is located about 75-ft. away from the house at our meter pole with the exhaust pointing away. All we hear inside the house is a very distant rumble. We have to be really listening in order to hear it running under load. When it's doing the weekly the exercise, it's inaudible inside the house. We live in the middle of 35 acres so the noise is a problem with neighbors.

Bill
 
   / Generator install, sizing, location #23  
I did find I can add a "soft start" module to the geothermal compressor to cut the start load by 75%, so that is a good safety net if we have issues running the system off a generator. 12-14kW is looking better and better.
I dont know how electrical soft start can work on something that starts under load - might want to research critically. However, I bet you are starting a pump and a blower fan simultaneously. These could be sequenced a second or so apart to great benefit.
larry
 
   / Generator install, sizing, location #24  
I dont know how electrical soft start can work on something that starts under load - might want to research critically. However, I bet you are starting a pump and a blower fan simultaneously. These could be sequenced a second or so apart to great benefit.
larry

There are several types "soft starts" available. Most rely on a timer of sorts on the start winding. However most modern scroll compressors do not start under load. First of all they require centripetal force from running to fully seal the scroll. Next since the units under discussion are geo units, generally pressures remain lower, and if the TXV valve is a bleed type, there will be no pressure when starting, until the system is pressurized, which can take 10-30 seconds.

I have no problem starting my 2 ton geo heat pumps with my 10 KW generator, without any special start up assistance.

paul
 
   / Generator install, sizing, location #25  
Thanks for the insight into the use of scroll type compressors. I was thinking of piston type. I guess theyve been displaced these days. I too have no problem starting my house A/C with my 10/12 KW gen even when running other house incidentals.
larry
 
   / Generator install, sizing, location #26  
My house geo unit is easily handled by my 12kW Kubota gen set. I think the breaker is 50amp and locked rotor is around 32amps - just for some idea. When the standby unit is used during a winter power outage - the clothes dryer doesn't get used at all. Stove (electric) used carefully to try and give room for other things to run (well pump etc.). I generally have a volt (multimeter) meter connected to an outlet so I can monitor the generator voltage - I have found dirty fuel filter = low voltage.
Thanks
 
   / Generator install, sizing, location #27  
Yourbreaker will always be lower than locked rotor. Otherwise it isnt protecting the compressor motor and the only thing that will blow it is a serious problem. A breaker is made to have a delay before it breaks on overload. The startup overload doesnt last long enuf.
larry
 

Tractor & Equipment Auctions

1995 Pro Sports 22ft Center Console Fishing Boat with 25ft T/A Boat Trailer (A48082)
1995 Pro Sports...
ECOA Trans-A-Dok TAD-50-608 Loading Dock Lift (A49346)
ECOA Trans-A-Dok...
2018 John Deere 8370R MFWD Tractor (A50657)
2018 John Deere...
2015 Ottawa Yard Spotter Truck - Cummins Diesel, Allison 6-Speed, Hydraulic Air Fifth Wheel (A50397)
2015 Ottawa Yard...
2016 Ford Explorer SUV (A50860)
2016 Ford Explorer...
Craftsman T1800 42in. Riding Mower (A49346)
Craftsman T1800...
 
Top