Running Costs

I need help with the following please

I have to advise customer running costs between the following:

12 Kw Mitsubishi FD 501 DT Cassette system, Inverter , running amps are 17 amps

or 12 Kw Mitsubishi FD 501 Cassette system 3 Phase . manual says running amps are 7 amps, I presume thats 7 amps per phase

Kindly advise

Well 3 phase tends to have better torque chararistics and and such and les start surge, and tend not to have such a voltage sag on start up, All in all the 3phase is best bet.

As for details to many veriables with to little data to plug into them.

Hi Abe

To evalute running costs you have to convert the running amps to Kwh (kilowatthours) - the basis for how electricity is costed.

To convert you need to multiply the running amps x voltage x running hours .
So, for your single phase unit it would be:
17 (A) x 230 (Volts) x ? (hours per year) x cost of electricity

and for the 3 phase unit it would be:
7 (A) x 720 (volts) x ? (hours per year) x cost of electricity

The cost of electricity can be found from the customers last bill. The total running hours can be estimated from his intended use (hours per day x days per week x weeks per year)

From the running amps you stated, it will be more expensive for the 3 phase unit.

MG Pony, the 3 phase will ahve a bigger starting torque because its a non inverter.
The first one is an inverter on 240 VAC and will not have a starting torque at all.
The overall cost for the inverter will be smaller but what is also very important is the comfort, how you feel the cold draft. Far less with an inverte because they increase evaporating temperature if possible.
And this better comfort is something you can't calculate.

Thank you Pny Frank and Peter

Actually , the customer is less concerned about running costs, I have the choice of fitting either a 3 phase system or the new inverter.

The inverter is only about a hundred pounds more dearer, but I was after a system which is smoother and more reliable..

I am placing the order on Tuesday, I think Im going for the Inverter system

Thank you