how to calculate electrical maximum demand?

Question

I need to calculate the maximum demand for a tunnel boring machine in order to select the correct generator.

Answer 1

Get the electrical specifications for the machine. The machine has to have a "nameplate" that will tell you the electrical requirements. If no nameplate is available, there should be a main breaker or fuses on the machine that will tell you what size circuit the machine uses. I'm guessing that the machine itself runs on diesel fuel or gasoline, so look for the electrical enclosure on the machine and try to find a nameplate. On the nameplate, look for "MCA" , "FLA" , "A" , "OCD" ; there are different abbreviations that are used to tell you the total amps of the machine. Once you know the amp rating of the machine , you can use ohm's law to find the watts needed to supply the machine. Try to find that info. and if possible, re-post the different values you see on the nameplate and we'll tell you what they mean and the generator size you need.

Answer 2

I'm making the presumption that the boring machine is available for inspection and the electrical plate is missing.
Use the tunnel boring machine power cord to find the generator size. The boring machine has a plug on the end of the cable. Use the pattern of the prongs and compare it with others as determined by Electrical Manufacturing standards. You can find this info easily at any electrical supply outlet. This will tell you the voltage and type the machine needs to operate. Then disassemble the plug and find out the number and size of the conductors. The size of the conductors have a maximum amperage rating. Use this rating multiplied by the voltage of the boring machine. The answer is the smallest effective generator size. It will handle the starting load, running load and probably some lights or tools once the machine has started boring.

Answer 3

If the boring machine has a spec for stall current, which is the maximum current it will draw, get a generator with at least that amount of current output. Of course, the voltage needed by the boring machine must match the voltage supplied by the generator.

Answer 4

Do you. I am surrprised. If this is a large electic motor it will be plated and most of the infomation will be stamped on the plate. There are other problems but if you lack this basic knowledge then you need to go on a training course

Answer 5

it depends on size of your boring machine
you probably know that in kW or hp
your generator will be rated in kVA
you will need more kVA than kW at least 25% more, play safe and go for approx 50% more
if machine rated in hp then kW = 0.75 times hp

Answer 6

No info plate anywhere? You need to know voltage and wattage, or running current. And - important, the under load current/ wattage.

Answer 7

amps = watts / volts. Remember that as load increases, so will the current, so allow a safety margin.