Question about step down transformer Canadian machine sending to Nigeria

[daveinarmstrong]

Hello,
I am sending a machine to Nigeria from Canada. This is a laminating machine and has a heater and 3 phase motor and a temperature controller. I know the temp controller will work on 50hz. The machine originates from the USA and runs on 230VAC 3phase 60hz. I am running it at 208Vac 60hz in Canada with no problem. I need to set the machine up to run in Nigeria where the power is 380V – 440V, 3phase (4 wire), 50Htz. My electrical contractor is suggesting i use a 208V to 480V transformer in reverse because this is what he uses here in Canada to run 380V 50hz motors that come from the UK. I am worried about sending this machine all the way to Nigeria without testing this setup.
Has anyone run into this before and come up with a solution?
Thanks in advance for your help.

 

[PRR]

I trust you have vetted your Nigerian buyer.

The motor starts (and lugs) with Volts. This is usually not critical, unless a motor must start against a heavy load. Fans and saws are easy. Air-compressors are hard.

The motor spins by Hz and will turn 50/60 or 83% speed.

The heater goes by voltage and your "480:208" conversion on 380V-440V line will give 165-190V. *Power* (heating ability) goes by square of Volts. The 79% volt condition will give only 54% of heating capacity.

SO: will it even start at 165V? If it starts without paper in the rollers it may do fine. If it has a lot of gearing-friction it may not. If it ever has to re-start after a jam with stock in the rollers, it may hum and burn.

If it starts, in this application the slower speed slightly compensates for the lower heat. But 83% speed at 54% heat sounds half-baked. If the heaters are very ample so that the temp controller has them cut-off much of the time, then on lower voltage they may just run more of the time.

> I am worried about sending this machine

I would worry too.

There isn't a real good/handy way to make large 50Hz 3-Phase power in Canada. (10 watts 50Hz for a record-player is easy, but not the size that 3-phase implies.)

I hate to sour your deal, but I think the Nigerians should be sourcing from UK or other euro-style market. Alternatively: they may burn-up your motor and replace it with a similar size known to work locally, and add tap-up transformer until the heaters glow well. So you might even wish to amend the deal to ship no-motor and customer to supply 208-240V for heater.

 

[telectrix]

i'd send them the machine foc in exchange for the £10m that they keep wanting to transfer to my bank account.

 

[daveinarmstrong]

i'd send them the machine foc in exchange for the £10m that they keep wanting to transfer to my bank account.

ha ha

- - - Updated - - -

I trust you have vetted your Nigerian buyer.

The motor starts (and lugs) with Volts. This is usually not critical, unless a motor must start against a heavy load. Fans and saws are easy. Air-compressors are hard.

The motor spins by Hz and will turn 50/60 or 83% speed.

The heater goes by voltage and your "480:208" conversion on 380V-440V line will give 165-190V. *Power* (heating ability) goes by square of Volts. The 79% volt condition will give only 54% of heating capacity.

SO: will it even start at 165V? If it starts without paper in the rollers it may do fine. If it has a lot of gearing-friction it may not. If it ever has to re-start after a jam with stock in the rollers, it may hum and burn.

If it starts, in this application the slower speed slightly compensates for the lower heat. But 83% speed at 54% heat sounds half-baked. If the heaters are very ample so that the temp controller has them cut-off much of the time, then on lower voltage they may just run more of the time.

> I am worried about sending this machine

I would worry too.

There isn't a real good/handy way to make large 50Hz 3-Phase power in Canada. (10 watts 50Hz for a record-player is easy, but not the size that 3-phase implies.)

I hate to sour your deal, but I think the Nigerians should be sourcing from UK or other euro-style market. Alternatively: they may burn-up your motor and replace it with a similar size known to work locally, and add tap-up transformer until the heaters glow well. So you might even wish to amend the deal to ship no-motor and customer to supply 208-240V for heater.

What specs should i have to get close to 100% heat and close to 230v for the motor?

 

[Knobhead]

If that’s the advise from you’re electrician get rid of him.
You can not “just connect a three phase transformer in reverse”. It would have no reference point to earth, unless you buy an extra ZigZag high impedance earthing transformer to connect to it. It would cost more than you’re machine to have made. You need a 230 / 415V ∆Y transformer with the secondary Y point solidly grounded. You don’t give the machine loading so I can’t advise on KVA rating.

 

[daveinarmstrong]

If that’s the advise from you’re electrician get rid of him.
You can not “just connect a three phase transformer in reverse”. It would have no reference point to earth, unless you buy an extra ZigZag high impedance earthing transformer to connect to it. It would cost more than you’re machine to have made. You need a 230 / 415V ∆Y transformer with the secondary Y point solidly grounded. You don’t give the machine loading so I can’t advise on KVA rating.

Hi Tony. The machine loading is 20amps.

 

[Knobhead]

I should have asked the load at a voltage. But here's two options

For 400V to the machine @ 20A = 13.9KVA
For 230V to the machine @ 20A = 8KVA

Because there is a motor involved you need to add 20% to the KVA rating to accomodate the starting load. So:
13.9 + 20% = 16.6
8 + 20% = 9.6

To keep the cost down you need a standard sized unit so either 17.5 or 10 KVA should be off the shelf units.

Let us know how you go on.

 

[daveinarmstrong]

Temco is advising:
TEMCo Custom Transformer - 15 KVA, Three Phase, 50/60
Hz, 400V Delta Primary, 230Y/133V Wye Secondary,
Aluminum Wound - 150C Temp Rise, Indoor Enclosure,
TP1 Efficiency at 60 Hz Operation, UL Listed.
This would be 400V 3ph to 230V 3ph.

 

[Knobhead]

That is the information you're supplier needs. BUT skip the aluminium wound, they are nothing but trouble with humid enviroments.