240 V 50 Hz to 60 Hz conversion - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: August 01, 2017, 02:16:04 pm
content: A friend is selling a very expensive automotive diesel pump test bench outside of the UK to a country with 240V at 60Hz mains, and he wants to test the control circuitry that draws a max of about 1 Amp on 60 Hz. he expects it will be ok, but would rather KNOW it works fine on the higher frequency supply. Is there a cheap and cheerful way to convert our UK 50 Hz 240V AC mains to 60 hz and allow a current draw of about an Amp please? Thanks.

author: BradC
author_rank: Super Contributor
timestamp: August 01, 2017, 02:19:06 pm
content: Get an APC SmartUPS. Cold start it on battery and it'll default to 60Hz. They only crank down to 50 once they see it on the input.

author: oldway
author_rank: Super Contributor
timestamp: August 01, 2017, 02:28:06 pm
content: Quote from: BradC on August 01, 2017, 02:19:06 pmYes, that' a good solution but be sure output is pure sine wave.Another solution should be to use an audio power amplifier 500W, a 60Hz sine generator and a transformer to increase output voltage up to 240V ...but this is a little risky to damage the amplifier.

author: Ian.M
author_rank: Super Contributor
timestamp: August 01, 2017, 02:34:17 pm
content: A function generator with 60Hz sinewave output feeding a high power audio amp capable of at least 300W pure sine output into a 4R load (so music 'power' in excess of 1KW) feeding a 30V 250VA transformer wired backwards as a stepup. Put a 25W 240V incandescent bulb or heating element across the original primary so its damped and doesn't run unloaded, otherwise you risk blowing the amp. Derate by the crest factor or your load, or again you risk blowing the amp.Other transformer ratios are possible depending on the amp's minimum load impedance and peak output voltage. If all you can find is a >500W per channel (music 'power') stereo amp, you'll get the most out of it by inverting the input signal to one channel (assuming its got a shared PSU for both channels - if its got seperate PSUs you can drive them in phase) and, on its outputs, using two separate transformers stepping up to 120V, with their original primaries in series for a full 240V.Its not *cheap* unless you can buy, beg or borrow a used amp . . .

author: BradC
author_rank: Super Contributor
timestamp: August 01, 2017, 02:37:34 pm
content: Quote from: oldway on August 01, 2017, 02:28:06 pmWhich is why I suggested the SmartUPS. Generally found cheap second hand.

author: Zero999
author_rank: Super Contributor
timestamp: August 01, 2017, 06:31:47 pm
content: Quote from: Chris Wilson on August 01, 2017, 02:16:04 pmThe cheapest way is to use a variable frequency drive, with a nice big filter on the output to get rid of the high frequency components, and set the output frequency to 60Hz. It won't produce the best sine wave, as no matter how good the filter is, some of the harmonics will get through.

author: Ian.M
author_rank: Super Contributor
timestamp: August 01, 2017, 06:48:02 pm
content: Take a small petrol generator (non-inverter type) and tweak the governor till its running at 60Hz, (20% overspeed) then use a Variac to adjust the voltage to 240V. Its probably worth loading it down with a few 100W bulbs so its more stable against load variations of the D.U.T.

author: edpalmer42
author_rank: Super Contributor
timestamp: August 01, 2017, 06:59:32 pm
content: Some of the smarter UPSs can be set to output 50 or 60 Hz regardless of what's coming from the mains. I have a Liebert GXT 2U that apparently has that feature. I've never tested it.Ed

author: edavid
author_rank: Super Contributor
timestamp: August 01, 2017, 07:00:25 pm
content: The product you want is called a frequency converter. Here's an example:http://www.magnuspower.co.uk/products/frequency-converters/lf1-400/If this is just a one off project, you can rent one from a test equipment dealer, or you may even be able to get a demo unit for a few days.

author: Chris Wilson
author_rank: Super Contributor
timestamp: August 06, 2017, 06:35:12 pm
content: Thanks for the replies, he borrowed a UPS that worked on a 60Hz output run off accumulators, which neither of us would ever have thought off, and the control gear was quite happy with it, many thanks from us both!!