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Hi guys,

I know nothing about electrics etc :confused: so please bear with me whilst I make myself look dumb :rolleyes: :rolleyes:
I ve just managed to pick up a Sayha SSM50 power hammer at a decent price :D It is 3 phase, the problem I have is that I dont have 3 phase electrics in my workshop.

Has anyone used a 'phase converter' to run one? or converted to single phase?

The only phase converter I have found available so far has a MAX HP of 5.5, 4.0kW at 32amps (power hammer motor is 4.0kW), I presume I need to go slightly larger to allow for the initial draw on start up?

Any help would be greatly appreciated!

cheers

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When you use a phase converter you will have a drop 20% in hp. I had a 5hp air compressor that was 3 phase and put a single phase 5hp motor on it, cheaper than buying a converter. IIRC, your hammer has a 10hp motor on it, with a 20% drop that would make it an 8hp motor. Probably would run the hammer but not as effecient. I'm sure others will give their opinion as I have....

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they take a fair bit of shunt to start them (the hammers), ive had problems with customers not being able to run hammers from static phase convertors, even though they are 'in capacity'

Best bet, in my opinion, is to find a larger 'rotary' unit (the type with a slave motor to generate the 3rd leg)

Have a google for transwave power capacitors to see the type I mean. They go up to 10hp as standad (off the shelf).

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I was assuming you were talking about a "rotary" phase converter. If it's a static forget it. They work O.K. things that have little starting load and don't need all the rated HP like a grinder or even a lathe. but only give something like 2/3 power.

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I run a 10hp with idler motor in the shop all the time as all my equiptment is 3 phase and when I moved to my home it became a must.

Non issue, works fine. If you can, I would strongly recommend oversizing as you will end up with other equiptment you want to run even if you dont have it now.

I put in a 3 phase panel right next to the single phase one and feed it from the converter box. We run about 10 different sanders and mills off the panel and just have to think about max HP running or starting at the same time. We are a 2 man shop so its not too hard but I am outgrowing it. I see a 15hp system in my near future.

A 10 hp rotary converter is usually rated for 10 hp MAX motor size for starting and can be used with 15hp of motors running all at the same time.

Be aware that many air compressors often dont have air unloaders and are hard starting. A top quality unit might have a clutch on the motor that allows it to come up to speed before engaging.

Personally I bought a 10hp thinking of a CNC mill or lathe as they usually are that size. I just bought a control box off of ebay from someone with high feedback and attached my own motor for the idler. I think it was under $500.00 and is now 6 years old with no issues. My incoming power here is horrid with spikes and line drops and still no 3 phase problems. I do turn off the breaker feeding it when not in use.

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The 50 kg say-mak runs on a 5hp single phase very nicely. This is due to the fact it runs a cogged belt drive they are much more efficient than v belts. When Tom started importing these hammers they came with a triple v belt drive and a 7.5 hp motor. Very few people could use this in a home shop. We went to work on this problem. We rolled a band to shrink over the V grooves on the flywheel installed a cogged pulley and a 5 hp 1 phase motor. There are over 200 units in use with few problems. as far as I have heard 1 man just replaced his first belt in seversl years professional use. If I were you I would go that way unless you plan to buy more 3 phase stuuf. I have been using my home made rotary for 18 years with not 1 problem.
Phil

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I'm with you there, John. I'll bet they put a bigger motor on because of the poor voltage in many countries they go to. They do seem to use rather big motors. The 2-B Nazel (180-200lb depending on year) used a 7.5HP motor. My 500lb Nazel ran for 75 years on a 15hp motor. Anyone put a ampmeter on one to see what they're drawing? Motors only make as much hp as they need for the load.

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I don't know if the 50 kg needed all 7.5 hp but it needed more than 5hp with a v belt drive. 6 hp may have been enough but 7.5 is the next step up. I don't understand what you meant by the belts would melt in seconds. I am not an engineer but I have been told cogged belts are 98 to 99 % efficient versus 70 to 75 % for V belts. Could be wrong info. I do know 5 hp is enough with cogged but not with V belts. If anyone can explain I'll be gald to know the difference.
Phil

P.S. same motor, same hammer, same day, same pully size, full load amps on motor 25 amps metered on Vbelt 27 amps. with cogged belt 21.

Edited by peacock
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The difference in power (5HP vs. 7.5HP) between v-belts and cogged belts has to come from somewhere. Differences in the heat, noise, vibration, ect, generated by the different belts.

I don't understand what you meant by the belts would melt in seconds


If the most of the difference was in heat generated in the v-belt due to friction between the belt and pulley and the bending of the belt it could lead to melting belts. Edited by Will. K.
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I heard back from Gates belts they say V belts can be as high as 95% efficient if properly maintained and installed. However this may decrease as they are wrapped around smaller diameter pullies. They also said V belts take more maintance. Cogged belts 98 to 99% efficient Not much different if properly maintaned.
Phil

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Well I managed to borrow a phase converter (static) to try, it started the hammer but the hammer would stall whilst doing anything other than idling :(

I have had a look and it runs a cogged belt so I ve now got to do some research on price of single phase motors compared with VFD

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hc1982te.....

Using a static converter results in reduced power at the tool (approximately 2/3rds of rated HP). They should only be used where the tool motor size significantly exceeds actual need, and never when the tool starts under a load. A rotary converter provides fulll power, but power load must still be considered. If the tool starts under a load (or is sensitive to power), the rotary converter idler motor needs to be larger than the motor of the tool. A general guideline would be 1.5 times, but under some conditions (extreme load, or electronic control power sensitivity) an even larger idler motor is needed.

VFDs for small motors are reasonably priced (I just bought one off eBay that will handle a 3 HP motor for a little over $200), but when you need to drive a larger motor, they get very pricey.

You can buy a complete rotary converter (google online to find prices), OR..... if you don't need super clean and/or balanced power, and you can find a surplus 3 phase motor somewhere (surplus yards or re-cycling operations commonly have they for sale), you can either make a rotary converter (look for instructions online), or buy a black box (panel, containing the required capacitors, relays, timers, etc) and make your own at a considerably less cost. If you buy a panel and provide your own idler motor, be sure you talk to your panel supplier about what you are using the converter for. In cases where a balanced 3 phase environnment is needed, a commercial converter may be required.

It is even possible to create a usable 3 phase power source without any electronics (most economical) if you have the means to get a 3 phase motor spinning (usually with a pony motor) before power is applied to the idler motor. This, however, provides an unbalanced (amps and voltage distribution) environment and requires more than just flipping a switch to get your converter running.

One more thing... If you are seriously considering swapping out the 3 phase motor for a single phase motor.... you need to consider that 3 phase motor provides more power (torque) than single phase motors (at the same horsepower). If your machine requires the size motor (horsepower) it has on it, and you want to use a single phase motor, you may need a larger horsepower single phase motor. I recommend talking to the hammer manufacturer about power requirements before you swap motors.

Good luck with your project...

Edited by djhammerd
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DJhammered has some really good information. A few notes: If you use a VFD as a phase converter it needs to be one size bigger, so you'll want to price a 7-1/2 HP VFD.

I don't agree that a 5HP single phase motor has less torque than a 5HP three phase motor. Horse Power is a measure of torque at a certain RPM, so in order to produce the same HP at the same RPM they MUST have the same torque. Now, that said, three phase motors DO have better STARTING torque.

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My experience with cogged belts in my protoype self-contained hammer is that the cogs on the belt shear and/or erode easily. It is tempting to use cogged belts to achieve the small motor pulley needed to get a suitable drive ratio. Tom Clark told me that the Europeans use 50cycle current so that with 60 cycle current here in the USA the machines runm too fast, and that he also found use of no cogs on the big pulleys (the shrunk-on rims) allowed enough slippage to avoid problems. I solved my speed problems using V-belts with a 1200 rpm 3 phase motor. AND, since that long ago time, thetire hammer has come along with its version of the speed solution. The variable frequency gizmo is perhaps the most elegant method, though pricey.

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Let me first start by saying that I am not an electrician. I purchased my first Anyang 165 which had a 10 hp 3 phase motor. I had heard that the rotary converter was the way to go and I had used TemCo a large converter supplier in the past for a cold cut saw. I gave them all of the specs and told them it should be considered a "hard start" and if they made a mistake, sell me a converter that is "over sized" for the 10 hp motor. I got my first converter in, hired an electrician to hook it all up, and it did not work. I called TemCo and told them what was happening and they said that it must be a "really hard start" and they would replace the converter with a larger one that would absolutely do the job. I re-hired the electrician to change out the converter (had to upsize some of the starting gear)... and pulled the switch... it did work if I wouldn't mind removing 2 of the belts, run the hammer with no guard so I could hand crank the flywheel at startup... bottom line, it was not a good situation. I called TemCo back and they were floored that the converter would not run the hammer... so we upsized again. (and more electrician expense). TemCo was good to work with in re-supplying converters but freight and electrician costs killed me. From this experience, sizing rotary converters appears to be as much an art as a science... it stumped even one of the larger rotary converter companys in the US. I have not tried VFD systems, but I am getting ready to try them out. I also considered building an idler pully and or a pressure relief valve to make startup easier... but my key lesson with the rotary 3 phase converter is upsize and work with a company that will keep working with you to make it right... and it's a lot cheaper if you have a relative that is an electrician.

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To: Jamesrjohnson. From: IRBlacksmith. Sad story. Never had such a problem, but then I have a 40HP rotary PC and always had 3-phase before that. Too bad they don't put compression releases on the newer hammers. Nazel and Chamberburg offered them and the Nazel just had a pipe plug where you could install one.

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Hi James, I remember that saga! glad your sorted now.

One of the problems is that new hammers are 'tighter' than 20 year old ones.

This is good, shows they are manufactured to close tollerances, pain in the ar$e if your on the limit of your power. A couple of hundred hours use and they free up a lot as they bed in.

I was having a chat with Mooney the other day. Hes put a VFD on a 15 kg Anyang, and says the result is truely amazing. Almost infinate control of power.

Ill get a 3 phase motor for one of my 33lb'ers and VFD it,. course ill post the results & videos here first ;)

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One thing about going down the 3 phase road is that 3 phase motors are alot cheaper than single phase. So in the future if you burn up a motor 3 phase is much cheaper to replace. Or if you get a piece of equipment without a motor, it easier to get it going. Especially as you get into bigger motors.

Get rotary over static. Bigger is better, for the unknown future.

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