60hz Motors and 50hz Electric Supply

Yes, no maybe. You didn't search first, did you? Your motor will run at 5/6 speed, so the pump will not perform as well. This subject comes up every day here. Do a search in the boxes to the right of this screen for 50/60 Hz operation.

http://cr4.globalspec.com/thread/37852/Running-a-50-Hz-Motor-at-60-Hz

Thanks Lyn. Maybe I missed it, but all I saw was 50 hz motors running on 60 hz supply. I have a 50 hz supply, and was wondering what problems to expect. I live in the Missouri Ozarks, with 60 hz motors, but my step up transformer puts out a 50hz supply.

It's just the opposite. No major damage, just that a normal 3450 rpm motor will run at 2875 rpm and the pump will pump less water. You may see some added heat and the efficiencies will be less, but it will work.

My sister lives in Harrisonville and commutes almost monthly to the family farm outside of Hot Springs, Arkansas. My avatar is a photo of some of the farm.

Thank you Lyn, I feel better already. I have a lot of money and time invested in my back up system, but I did not want to burn everything up. I run a Mac computer, and I been told it does not pllay well with Modified sine wave, so I will have to get another inverter just to use it. Again, thank you.

Your MAC may be fine on 50Hz. Lots of stuff is rated for 50/60Hz service.

Check the owners manual.

Yes, it may well operate on 50hz with no adverse problems, but I was thinking I needed a true sine wave to run it, not modified. But, like most things I`m probably wrong, but it don`t hurt to ask. As far as the owners manual, with all the stuff in my radio shack, I`m sure I can find it, I just don`t know if I want to expend that much energy right now. Again,thank you.

Electronics need PURE sine wave :)

I agree with you Fredski, thats why I`m looking for another inverter that will run my Mac computer, and the only transistor radio I got , my Kenwood 850S. Fortunately, I can run the Kenwood in 12 volt mode. But I agree with you. Thanks for your help. Bob KC0VEA

Hear, hear.

What a racket inverters make on audio equipment. What are those lines across my video?!

There is a V/Hz/rpm relationship with motors. If the motor is designed specifically for 60Hz at 220V, at 50Hz it should have about 183.3V. There are exceptions. Specially with single-phase motors. Three phase is fairly simple. The frequency/speed relationship is: frequency divided by number of pole pairs times sixty (seconds, to get rpm), minus percentage slip. Example 50/2 x 60 - 5% = 1425rpm

Can't you set the V/Hz relationship on the inverter? Consult the manufacturer, on the Internet if you don't have a manual.

Other: My PC and equipment works fine on a PWM inverter with an isolating 1:1 ratio transformer. It seems to get rid of the pulses and I can ground the neutral.
Isolating transformer not necessary for motors though, unless there is a capacitor start circuit.

But at 50Hz it probably won't pump anyway, as PW Slack in #26 and I in #13 pointed out.

Cheers.........Codey

Not from that depth, for sure!

And me in #10.

He's not going to be running at 50 Hz, he mistakenly thought that a step-up transformer rated for 50 Hz operation would give him 50 Hz out; what it's going to give him is 60 Hz out, because the inverter output is 60 Hz, we cleared that up a few posts back. So, the only questions I would still have are: can the inverter handle the start-up current, and will the pump be OK with a modified sine-wave being fed to it.

Tom D.

I note in the specs "16,000 watts surge capacity" and "soft start".

Do we know the pump watts or type of pump?

Do we know the transformer VA?

In my experience 'modified sine wave with phase correction' runs everything quite happily. I've known small generators to produce messier power.

It's the square wave ones, and the liars about "modified" and "sine", that make motors sound like someone has thrown a hand full of nuts and bolts in. I'd just plug some other motor operated appliance into it, and have a listen.

I know, Tom. That was my first point in #10. Perhaps I should have phrased that post more clearly, as:

1) The inverter determines the supply frequency, not the transformer, so he is probably getting 60Hz already, not 50Hz.

2) If it were a 50Hz supply, the 20% reduction in pump speed would result in a 44% reduction in pressure, and depending on the rated pump head that might result in zero flow.

OK Holzfeller, sorry, I'd forgotten about that

Cheers.......Codey

.......and for a deep well, the performance curve for the lower speed for this pump needs to show sufficient lift available to get water to the surface. For example, if the depth is 100ft and the maximum lift on the 2840rpm curve is 90ft, then it isn't a pump any more.

A few questions to ease resolving your situation.

700 amps into the inverter, is that a purely 12V DC system, or are there higher voltages available?

Is the 'deep-well' pump a multi-stage submersible and happily running in the well?

Is the 50Hz on the transformer's nameplate, or the inverter's?

If the inverter is a 50Hz model it may be altered to 60Hz cheaply. If the items havn't been installed you might look at a submerged high-speed pump which will accept both 50 & 60 Hz happily.

It is a AIMS 8000 watt inverter, 12 volts in ,15 maximum in. I don`t know about multi-stage well pump, but this one runs on 220 v. AC. Its down 300 feet. The 50 hz is on the transformer nameplate. I have this system as back up, but with electric cost through the roof., I think I`m going to be off grid 5 days a week. I hope this helps you, so maybe you will help me. Thank you for your input. Everything is installed, and has been used for short durations. The only thing not turned on was my Mac computer.I used my old Windows computer with no problem so far.If I smoke it I ain`t out much. All my ham radios are vintage tube, no problems yet. I do have RF or AC hum in receivers, but better grounding seems to have eliminated that. I also interwined the positve and negative cables to help reduce magnetic forces. from being radiated. Again, thank you for your interesrt. Bob KC0VEA

I forgot to mention this inverter comes in different input voltages. 12-24-36-48. The 12 volt puts out 8000 watts, and will surge to 16,000 watts for I think 45 seconds. If it ain`t started by then, it ain`t going to start. The others come in mostly 5000 watts, some only 2500 watts. I thought this was the best buy for the money, and the watts. On sale for 799.00 plus free shipping. I watched it for a long time, and when the price dropped, I grabbed it. The step up transformer was 300 dollars, also with free shipping. They wanted 150 .00 for shipping, but they were not selling. When they offered free shipping, I bought mine. Hope this helps, and thank you for your input.

Hi, OM,

Just back from a fellow ham. One discusson was on reducing RFI on a modified sine 12 V DC to 240V inverter. The steps are 0.003ms ramps and probably direct from the switching transistors. Two problems to cope with here.

That fast edge will go down the Zo of the power cable, hit the missmatch at the pump and, being inductively terminated, ring with severe overvoltage on the winding's insulation. Any air-filled void is liable to develop corona discharge. The oxygen changes to ozone which eats the insulation. Motor burnout follows in a while.This effect is well known to happen with pulse width modulated inverters for motor speed control. The cure is an inductor input LC lowpass filter, just the same as to attenuate RFI on HF!

Capacitors on the inverter's OP,line to line or to ground, will take the transistors out of their safe operating area and failure follows, hence the inductors first. A delta of capacitors follow,proper mains-rated types or an ex equipment Corcom or similar filter can be used (gaining more attenuation) but only with the inductors first.

Your first priority is to get that inverter up to 60Hz, if the drive is from a microprocessor it may be possible to get it reprogramed or a changed chip or xtal or pcb. Best talk to the maker. Good luck,I will watch.

I might be missing something here, and electrical is not my forte, so please correct me if I'm wrong, but surely the supply frequency would be determined by the inverter not the step-up transformer. As far as I'm aware the transformer would change the voltage but not the frequency.

One more point, even if the well pump works OK on 50Hz, if the speed drops by 20% the flow will drop by 20% but the pressure will drop by 44%, so you might find you get no flow at all.

What size (output) do you have on your 12 volt side to supply 8000 watts at 220 volts? It must be very high current or else you have too many zeros on you power rating?? Penttijp

http://cr4.globalspec.com/member/45329/penttijp I have 10 batteries, 6 volts each. They are wired series-paralell. Each batter is 310 amp hr. This gives me my 12 volts power input. The inverter does the rest. It puts out 124.7 volts AC,at 60hz which goes into the transformer, which boost it to 240 volts AC, at 50 hz. I hope this helps. Thanks for your input and time. Bob KC0VEA

Inverters I've seen have adjustable output frequency, up to well over 60Hz. If yours is like that you can give the motor the 60Hz it wants.

If not, I doubt whether 50Hz will be OK. For a well pump, must of the head is likely to be static. At 50Hz the closed-valve head is ~ 69% of the 60Hz value, and may well be less than the static.

BTW, where do you get 700-odd amps at 12 volt DC from for any length of time? Just curious.

Cheers.........Codey

I may be assuming too much here, but I think the OP's inverter may be 60 Hz already. I think the 50 is coming from his description of the step-up transformer. If your inverter is running at 60 Hz, your 50 Hz step-up transformer is not going to change that, it's just not going to run at the same efficiency as it would at 50. Am I way off here? I still don't recall seeing a post that specifies the frequency of the inverter the OP is talking about.

A search for AIMS 8000W inverter found this:

• Continuous output power: 8000 Watts
• Surge power capability (peak power): 16,000 Watts
• dc input / operating voltage: 10 to 15 Volts · Output voltage: 120 Volts ac +/- 10%
• Output wave form: modified sine wave with phase correction
• Output frequency: 60 Hz +/- 1 Hz

So, it appears he's got a 60 Hz inverter, and a 50 Hz step up transformer, which may or may not be up to the task of running the pump. If it does work, it's probably going to be less efficient because it's optimized for 50 Hz. Tom D.

Yes, that sounds more like an inverter to give AC from a battery for emergencies, etc, rather an industrial inverter for motor speed control.

If his inverter matches the data you've posted, I doubt if he'll have a problem. I can't see the transformer performing significantly different at 60 vs 50Hz.

Cheers.........Codey

http://cr4.globalspec.com/member/6359/tdesmit You got it right sir. With so many responces I was going in circles.It is a 60 hz inverter, going into a step up transformer.The transformer boost the inverter imput to 240 v, at 50 hz. I have 10 batteries, 6 volts each. Each battery is 310 amp hours. Wired in series - parallel. The transformer is from 220 .com, and its rated at 0-8000 watts at 50hz. I tried to buy a transformer American made for 60 hz, but I could buy a new car cheaper. I hope this helps. Thanks everyone for your input.Bob KC0VEA

RC, your missing one of the basics of transformers here. It may by a transformer that designed to work at 50 Hz, but if you feed it 60 Hz, your going to get 60 Hz out. Transformers "transform" voltage, not frequency. The transformers' efficiency may suffer a bit, but it will probably do the job. The other question that has not been answered: will your pump like the modified sine-wave? The transformer is going to change the waveform a bit, and will probably act a filter of sorts, but you probably won't know until you try.......

Tom D.

Thank you sir. That was one of my main concerns was the sine wave. Its modified, and going into the transformer would act as a sort of a filter. I discussed this on air with some retired radio engineers, and they felt it would work also. But I know you guys on here are way smarter than I`ll ever be, so thats why I asked. I don`t want to pull the pump again from the well, each time I do it cost me 900.00 .I sure do appreciate all the help from you fine gentlemen. I just purchased a KILL A WATT, and it will tell me the HZ at what everything is running at, along with the wattage. Again, thanks guys for your input. Bob KC0VEA

Protect your equipment with the right over current and over voltage devices and go ahead to use the step up transformer.You may wish to use a stabilizer,go ahead.

Thank you Patrick for your input. I intend to do just that. I`m going to go for it 5 days a week off grid. I do have a 500 amp fuse inline between the battery bank and the inverter.I also have a remote screen inside the radio shack telling me everything the battery bank is doing. I can access many features not normally available from the charger control itself.It plugs into the charger via a telephone like plug.I also have a panic button in the shack. I can shut down the inverter with the push of a button.I also have a battery disconnect switch also. Thanks for your input my friend. Bob KC0VEA

I just wanted to say thank you to everyone who contributed their advice and questions. This has been a real learning experience for me. Electricity is not my favorite thing to play with. Everyone laughs at me in my shack when they see me inside one of my tube radios, cause I`m wearing electricians line gloves. They are big, bulky, but they serve my purpose. If I need to change a tube, no problem. It just takes a little longer. I`m retired, I have all the time in the world. Many a operator has been found slumped over one of these old tube rigs. I been bit once, it ain`t going to happen again. Anything more serious than a tube, I have friends that do this all the time, and unlike me they know what they are doing. I talk on the radio, I do not work on them. I have better sense than most operators.Not knowledge, just common sense. Again, thanks everyone. Bob KC0VEA

Bob, I'd say that "common sense" has kept more people safe than knowledge, and it's no so common these days.......

It would be good to hear how things turn out for you, please do come back and let us know how things work out. Be careful around those batteries, that's a lot of power sitting there!

One more note; I've got a Kill-A-Watt meter, and it doesn't work too good on a modified sine wave source. You may get strange frequency readings (like double), and the voltage may not be too accurate. I would say you would need a true RMS AC voltmeter to get an accurate voltage measurement. Not too sure how it does with Amps/Power. It's still better than nothing at all for monitoring how things are going.

Tom D.

A lot of my friends call me Dr. Bob. Its a term of indearment only I assure you.From my days of building antennas, and towers, where common sense won every time. I checked my Kill-A Watt, and you are right. Frequency is really weird, like 13, but the voltage is reading almost dead on compared to 3 other meters.Of course, they are all going to read the same until I use like you suggested a true RMS AC voltmeter. I think I have one of those here somewhere in all this mess. I guess I need to check all my appliances BEFORE I start using this inverter on a full time basis.Then I will know how many watts each pulls in one hour. Then I could more accurately know the limit to my battery bank.This has been a ongoing learning experience. I have made mistakes, and learned from them.Some were costly, others were somewhat funny, but I learned from all of them. I have several friends waiting for me to work everything out, then they want to copy what I did.I doubt many will as its costly, time consuming, and some what unnerving if yoiu don`t know what you are doing.Like John Wayne said: Life is tough, but its tougher if your stupid. Thanks TDESMIT for your concern and imput, and I will be back with updates. Bob KC0VEA

A good point of reference for your Kill-A-Watt would be to test appliances on the Public utility, record your numbers, and then again on the modified-sine inverter. I'm talking about for watts, amps and power factor, if you looking at that.

Tom D.