ICE MACHINE RATING

Hi,

Most likely that machine needs 3 phase supply and thus rating 380 V.

The higher voltage allows the power supply wires to be smaller (less current) for the same amount of power. Some devices have arrangements which allow the components to be configured to operate at a different voltage. Use a qualified electrician to make those changes if they are an option for that piece of equipment. Dual voltage devices are quite common.

Hello Joe,

Thanks for the response. Quite appreciate.

May I enquire further:

1. How is 380V higher voltage generated / obtained?

And how different is it from my 240V?

2. Can these differences be explained in 1-Phase, 3-Phase etc, etc, jargon?

Thank in anticipating your response.

Regards,

1 phase or single phase is simply just any one of the three phases distributed across the land by the power company. AC power is generated by rotating a magnetic field inside a set of coils spaced at 120° apart. One can also generate single phase power or even two phase power at 90° apart but the energy transferred to any set of coils goes to zero in between coils (i.e. polarity inversion requires transition through zero). By using three phases, two of the three are always in transition while the third goes through zero. Therefore, the generator is constantly transferring mechanical energy into electrical energy and it is consequently less bumpy. That is to say that producing or using three phase power is considerably smoother (less vibration - longer bearing life) than single phase.

Secondly small loads are easily handled by single phase motors. The size of single phase motors increases rapidly to handle vibration (pulsed energy translation) as the load increases. Larger loads like big compressors need more balanced motors and they use three phase power to translate electrical energy into much smoother mechanical energy.

All AC power is delivered at very high voltages because the primary problem with transmission is resistance which is only a problem for current. Consequently every user must transform the higher voltage to one that is more suited to your facility or equipment type. The 380 volt power is probably actually supposed to be 400 volts within a range of tolerance of ± 10%. If your normal residential voltage level is 200 volts then the larger appliances may use a higher voltage to keep the wire size small. Wire size determines resistance, so again to keep the current low, the voltage must be higher. Typically single phase power is transformed into a coil with a center tap. The voltage across the entire coil is twice the voltage from either end to the center tap. The center tap is also attached to ground so that the voltage from either end to ground is limited. Else, the potential for death by electrocution is higher.

Hi Joe,

Thanks for that detailed expose. It really cleared lots of grey areas.

I can now see that a 380V machine is actually designed to utilise all the 3 phases (4 service cables came from the service pole into my house) that the power company supplied.

Rest assured that whatever equipment I intend to install will be done by a certified expert.

But, what may happen to the operation of a 3-ph machine when one of the phases is inadequate or completely fails. I have seen such poor services on many accasions.

I do hope to hear from you again soon.

Cheers,

See http://en.wikipedia.org/wiki/Single-phase_electric_power for more on the topic. There is also another site http://www.allaboutcircuits.com that talks about AC power in volume II.

I sincerely doubt that you have three phase power coming into your house. If you do, it will come from three separate transformers. Otherwise you have only single phase power and it will look like this. The four wires most likely consist of two legs of 200 volts, a neutral, and a ground. The neutral is actually a connection to the point at which the two legs are connected together. The circuit voltage between the two legs is 400 volts because there are two coils in series on the secondary side of the transformer. Because they are the same phase and polarity, they add like two batteries in series.

Hi again,

- Is that 240V your main voltage or phase voltage?

- What is that ice machine's power rating and does it need 3 ph supply?

- Is your electricity distribution system 3 ph?

Atleast here in northern europe we have many machines rated to 380V that needs 3ph supply.

Main voltage is calculated from phase voltage by multiplying it with sqrt(3).

1ph 240V ~ 3ph 415V

Hi Flux,

Thanks for the response.

- The 240V is phase voltage.

- Machine's Power Rating 9 (Nine) kWh, 380V / 50Hz

- I think so, (4no. cables, Red, Blue, Yellow, Black) are dropped from the service pole by the electricity company.

Thanks,

NotUrOrdinaryJoe think outside USA!

M.A.Jibril may well have 3 phases. He is making ice BLOCKS not cubes.

One question he asked is what happens if he loses a phase. The answer to that is that he should have proper protection for the compressor of his freezer unit. There are various means available, from a simple motor protector that senses the increase of current (worthwhile anyway) to more sophisticated units that check maximum, minimum voltage and loss of phase problems and output a signal which can be used to disconnect the machine before expensive damage occurs.

regards

Chas