60 Hz to 50 Hz Conversion

It's probably cheapest to buy an off the shelf 40kW VFD.

They don't care what frequency is input and will output 50Hz. Plus they have excellent overload protection, V & I monitoring and power metering built in.

Thanks for the reply. Our Loads include Motors, Lighting and Battery charger. Can I use a VFD to take 60 Hz input and provide fixed 50 hz output. This fixed power can be further distributed as required. Ofcourse, voltage levels as required.

If this can be achieved, it seems the cheapest option as standard VFDs are available. I have to check with the VFD Manufacturers.

Many if not most or all VFDs can do this; you just program or enter on a keypad the desired output frequency. There may also be a voltage-proportional-to-frequency characteristic. This will fit your case pretty closely; 480V × (50Hz/60Hz) = 400V.

If the VFD cannot produce the required power (kw) at the reduced output frequency, then you can select the next higher size of VFD.

You will still have 480VAC, not 415VAC. There is a simple 2 transformer bank we use at our plant to convert three phase 480VAC to 415VAC. (actually about 408VAC, but close enough) See Acme transformer for wiring details. (we use this for simulating European voltages, but don't convert to 50HZ, since all our tested loads for lower voltages, although to be on a 50Hz source, are frequency independant - power supplies/vfd's -if we ever have to run a motor direct w/o vfd, then we too will need to change frequency)

Do you think this in conjunction with the VFD would give the required 415VAC at 50Hz.

Hi

VFD is the best solution in the case where amplitude of voltage and frequency are of significant, in VFD, the ratio of both is significant so VFD is better for motor load,

whereas for lighing and battery load, where the voltage level has prime importance, VFD can't solve the problem.

regards

Divyesh patel

A VFD will certainly do this job but when you mention lighting & battery chargers etc I am beginning to assume you want to feed a distribution board, then take smaller circuits off this.

A VFD produces HF noise on the output which requires you to use screened cable between the VFD and the motor. Usually this is close and not too big a burden. However if you go hooking a standard cable network to this output, you will create a nice big antenna and could end up with HF noise everywhere. Unless the cables concerned are in steel conduit for example.

I have not tried to filter the output of a VFD and don't fancy the results. Just my tuppence 'orth.

The VFD are better used for Motor drives not for static loads such as lighting and battery charger. we have better frequency converters available in market where a synchronous motor generator set will convert the available frequency to the frequency desired and the voltage can be converted through portable transformers as required. this is the most economical design as VFD's are very costly.

I was looking for a MG Set only in the first instance. However, if I can manage with a static converter, it will help in the operation & maintenance part.

Can you give me some vendor details who can supply MG Sets or Static frequency converters in the Middle East or India.

Which way is the conversion?

1- You have equipment designed to run on 60Hz 480V and you want to use them on 50Hz 415V ? or

2- You have equipment for 50Hz, 415V but power supply is 60Hz, 480V?

If 1) ** Motors will work OK except that the rpm will be reduced accordingly, therefore the output power (kW available on the shaft).

** Ordinary filament lamps will still work OK

** Anything having a choke or transformer will not be 100% OK. Must check the name plates to see if 60Hz is mentioned. Voltages must be considered, but might still be OK.

If 2) A Frequency Inverter for the Motors (3phase motors) OK

The other loads will have a problem mainly on the voltage issue: Transformer to drop the voltage will work for resistive loads.

For battery chargers and lights with chokes, Name plates references will sort some of them. Otherwise, the frequency / voltage combination must be looked at in terms of energy input... more dodgy without proper one by one study.

To decrease VFD size (price) you can also by-pass all resistive and non frequency sensitive loads if they can support the slightly higher voltage.

Wangito.

An AC drive can cause large problems if harmonics current distortion is an issue on your 480V feeder. Also mentioned above is the fact that the voltage regulation that you need for your loads is not the same as what is used on a motor. You would also need an isolation transformer for many loads as the output will contain large differential voltage spikes around the ground. There are issues about restart and overload that might not work well for you with most AC drive. It would not be a problem free application.

A properly designed AC/DC/AC converter like a UPS will do a better job. UPS are made for this application. You probably don't need the batteries or only a very small pack for added ride through capacity during brown out. If you cannot find a standard one off the shelf, drop me a line and I can make you one meeting your specific needs.