System traveling overseas

Hello all,

This is not a PLC question but I am sure there are people out there who can answer. We have a system that is going over sea's. Current supply voltage is 120vac 60hz 20amp, with the biggest load being a 1/2hp motor. The voltage will be 240vac 50hz(I think it 240, its going to Israel) . The motor can be wired for 240 but what happens at 50hz? I am sure the motor will run slower but can it be damaged, will there be excess heat build up? I have called the pump manufacture and no one seemed to know for sure what would happen. Thanks for help.

My experience with running devices (transformers, especially) at a different frequency is that they will heat up slighly more and should be de-rated when sizing them.

However, in the case of your motor, you will probably lose 1/6 of the HP. Heat shouldn't be a huge problem. The best bet is to always use a device that is either the correct frequency or dual rated, i.e. 50/60 Hz.

Be sure to specify and order the right part at the beginning, if you are dealing with a global market. Dealing with problems like this as an afterthought is a real pain...Who wants to send a $100 replacement part halfway around the world because it's not properly rated?

Assuming this is a 3 phase motor

You did not mention how you would control the motor etc. Lets say its a standard 4 pole 1800rpm motor at 60 hertz. If you run it at 50 hertz then use the formula rpm = 120 (constant) times 50 divided by 4 (number of poles) = 1500 rpm. Using direct on line starting then the torque/HP may need to be derated since it is running slower....BUT

Here comes an interesting feature, you can use a VFD and run it at 60 HZ which can output full torque etc using the 50HZ supply. Technically with this method the motor could be either 50 or 60HZ and offer the rated HP necessary.

Another thing I might consider since its going overseas is remove the 120vac and use 24vdc that can be powered from 240 single phase. I am assuming that 120 devices may not be as easily obtained as they would be here. This could eliminate issues with transformers etc.

Hi

Since your machine is comeing to Israel I will try to help.
1st.the outlet of one phase here is 220v 50Hz.
To get the best performance get motor which design for 50/60Hz.
The motor would work 20% less then in US.
The most common solution for that is to use VFD 1P to 3P if your motor is 0.5 hp its a piece of cake.
the motor would run on 60Hz after the VFD.
If you need any more help feel free to contact with me.

stooperbike said:

I have called the pump manufacture and no one seemed to know for sure what would happen.

Click to expand...

Consider getting a new pump manufacturer.

If this is a positive displacement pump, like a gear pump or a vane pump, you will have 83% flow and 83% power. If your pressure requirement doesn't change, you need to make sure you have enough torque and power to handle the system requirements at 83% speed.

If this is a centrifugal pump, you will only have 83% flow AND you will only have 70% of the pressure capability from the pump. You need to make sure this will handle the needs of your system!

Tom Jenkins said:

Consider getting a new pump manufacturer.

Click to expand...

Agree. The pump manufacturer should be able to provide you with the curves (data sheets) to figure all this out easily.

We ship a decent amount of equipment over seas and when dealing with 50Hz our 5HP 60Hz motor does just fine, but we have to use a different impeller in the pump to get enough pressure and flow (centrifugal pump). Your application may require nothing, a simple change, or a complete rework. Depending on how big a deal all this becomes a VFD might be the easiest solution.

Download Voltages of the World here:
http://www.aes-soft.com/votw_home.htm

It's free and very handy. It shows 230/400 50Hz, but Arik said 230. That leads me to believe it's 220/380 50Hz. This is the voltage in Jordan (next country over from Israel).

Think of the sine wave for 50 vs 60. The peak has a longer duration - a longer duty cycle. For something to work at 50, the windings are a larger gauge. It's cheaper to make a motor 60 Hertz only.
A 1/2HP motor is less that 200 bucks, but probably a lot more if it's for a pump. In that case, the suggestion for a VFD is probably the cheapest way out. AutomationDirect sells VFD's. Prices may be lower in Israel, so it may be best to buy local if it can be installed on site. Buying here allows you to program it here. It should still work the same in Israel - the VFD input is 50/60.

Even if the motor could take 50 hertz, it may be old now. If so, it may have it's "end-of-life" accelerated at 50 Hertz.
Replace it(possible reduced flow) or VFD it.

The price of VFDs here is significant cheaper then in US even then AD site.
I would supply and install the VFD in the States because the warrenty issue.
(make sure the vender of the VFD represent in Israel)
Check every thing with 2 phase of 220V instead of phase and neutral and just change base frequency before the shipment.


BTW. Israel and Jorden are not sharing the electrical supply like US and canada.
the voltage here is 380-400v/220-230v depend how you set your transformer.

can't you simply rent a generator for a week or two and see for yourself what happens before you ship the product?
just use google, you'll find places like this:
http://generatorrentals.com/

keithkyll said:

It's free and very handy.

Click to expand...

That is a great program. It is the first listing I've seen that covers industrial/3-phase voltages. Most sites like this only have household voltage.

Thanks!

Thanks for the help, I will leave it up to the customer and see what they want to do. i would like to sell a VFD with a new pump just because it would be fun to do, we'll see. I have a feeling that with there budget they will say let use the existing pump and "recalibrate" everything so it looks fine.

Just a note: 83% reduced power may not be correct.

I work with centrifugal pumps.
A centrifugal pump will run 50/60 cubed, thats 58%, less power when changing speed from 60 to 50Hz.

The pressure reduces by the square of the speed change.
The flow reduces by the ratio of the speed change.
The power reduces by the cube of the speed change.

So your motor will handle the load just fine, its a matter of your pump doing its work.

Please also consider that vane/gear/lobe type so called positive displacement pumps are not truly positive displacement at the lower end of the speed range , this is a function of viscosity and shear - all but the most expensive pumps will leak back through the pumping member at slow speeds , particularly with a low viscosity product . Maybe not important if the pump was sized correctly in the first place , but if the pump was sized assuming straight line performance , you could run out of puff .