Gene Arbogast
New member
- Location
- Tallahassee,FL
I have many problems-Here is one which is electrical in nature......
I need to size a diesel genset for a small country store.It has a single phase 300a service with plenty of 240v refridgeration loads,a mix of 120 and 240v coooking equipment,AC/heat,lighting and other typical 120v loads.
With all of their equipment running on a busy summer day(AC and fridge loads not cycling because of summer heat),A phase pulls approx 150 amps and B phase pulls approx.170 amps.
The client wants an ATS and does not want to do any manual load management by shedding loads via the Main Breaker panel or to add loads by turning appliances on that aren't needed for use.I believe there is a potential problem because diesel generators have a minimum rated load to be observed in order to prevent "wetstacking" of the motor which could cause costly maintenance. I believe that the minimum rating is typically 30% of the maximum rating.
My initial calculation is 247v times 170amps for approx. 42kw.I would then oversize this to 50kw to allow for start up of fridge compressors and fans.
Now I would like to do a minimum load calc for the business when it is not open and is using far less cooking equipment,lighting,etc.
I want these calculations for max and min load to be as accurate as possible and am hoping the good members here could steer me in the right direction...
More specifically,I would like to know how to count the 120v and 240v loads separately? I believe that this would be more accurate than multiplying the amp draw on one leg by the measured voltage.
thank you all in advance for any advice and opinions....
I need to size a diesel genset for a small country store.It has a single phase 300a service with plenty of 240v refridgeration loads,a mix of 120 and 240v coooking equipment,AC/heat,lighting and other typical 120v loads.
With all of their equipment running on a busy summer day(AC and fridge loads not cycling because of summer heat),A phase pulls approx 150 amps and B phase pulls approx.170 amps.
The client wants an ATS and does not want to do any manual load management by shedding loads via the Main Breaker panel or to add loads by turning appliances on that aren't needed for use.I believe there is a potential problem because diesel generators have a minimum rated load to be observed in order to prevent "wetstacking" of the motor which could cause costly maintenance. I believe that the minimum rating is typically 30% of the maximum rating.
My initial calculation is 247v times 170amps for approx. 42kw.I would then oversize this to 50kw to allow for start up of fridge compressors and fans.
Now I would like to do a minimum load calc for the business when it is not open and is using far less cooking equipment,lighting,etc.
I want these calculations for max and min load to be as accurate as possible and am hoping the good members here could steer me in the right direction...
More specifically,I would like to know how to count the 120v and 240v loads separately? I believe that this would be more accurate than multiplying the amp draw on one leg by the measured voltage.
thank you all in advance for any advice and opinions....
