static phase converter for soft serve ice cream machine

[jwrenn]

Hello all,
I was contacted to install a single to 3 phase phase converter for a soft serve ice cream machine at a local historical site. The info I was given was the machine has 2 plugs for 3phase power. The spec sheet calls for 20 amp 3phase circuits for each plug 208/250 volts. The motor specs are 2 -1.5 hp motors. My question is do I figure the converter based on the motor hp only or the ocpd requirements of 20 amps per circuit? The phase converter manufacturer says their static converters can run refrigeration equipment and 2 motors as long as they dont start simultaneously.

 

[StarCat]

Soft Serve Experience

Soft Serve Experience

Hello all,
I was contacted to install a single to 3 phase phase converter for a soft serve ice cream machine at a local historical site. The info I was given was the machine has 2 plugs for 3phase power. The spec sheet calls for 20 amp 3phase circuits for each plug 208/250 volts. The motor specs are 2 -1.5 hp motors. My question is do I figure the converter based on the motor hp only or the ocpd requirements of 20 amps per circuit? The phase converter manufacturer says their static converters can run refrigeration equipment and 2 motors as long as they dont start simultaneously.

I would advise you take a closer look at the machine to verify whats being run to be sure your outboard device is correct.
This sounds like a dual or tandem style unit. As thus it has 2 drive motors and very likely 2 separate refrigeration systems, which means 2 compressors.
Your 20 amp circuits are likely fine, but its not just the dasher motors you are starting. Depending on how the control system are set up, things definitely can start at the same time. I have worked on a number of these types of units that are set up in this manner.

 

[norcal]

How will the compressors not be running at the same time? You cannot rely on the user to only start up one at a time, two static converters, or better yet a rotary converter would be needed, & with a rotary converter you would not be single phasing the motors after start up like you would with a static, plus doubt the soft serve machine manufacturer oversized the compressors & they usually are derated 1/3 with static converters .

 

[John120/240]

Educate Me: What is the advantage of a phase converter (static or rotary) vs the appropriate transformer ? My guess is that the phase converter will only operate when the ice cream machine is operational vs transformer would be 24/7. Any others ?

 

[GoldDigger]

Educate Me: What is the advantage of a phase converter (static or rotary) vs the appropriate transformer ? My guess is that the phase converter will only operate when the ice cream machine is operational vs transformer would be 24/7. Any others ?

A transformer cannot change single phase to three phase.
If you have three phase service a (three) transformer(s) can give you different voltages.

 

[John120/240]

A transformer cannot change single phase to three phase.
If you have three phase service a (three) transformer(s) can give you different voltages.

Duh, Selective vision & a major brain fart. Thanks Gold

 

[Sierrasparky]

I'd use a rotary phase converter or get them to order single phase units

 

[kwired]

I agree with others. Static converters are for single motor applications, rotary converters work with multiple motor applications.

getting a single phase machine would be the best action to take if three phase is not available.

 

[Jraef]

Or because most likely the motors are the only 3 phase loads, separate out the motor circuits internally and install small VFDs on them, even though you will not vary the speed. 1-1/2HP VFDs capable of phase conversion will likely cost you less than $200 each. A little more tricky to do because it involves getting into the internal wiring, but in reality you should do that no matter what because you must make sure no controls are tapped off of the manufactured leg.

Example: http://www.factorymation.com/Products/FM50_230V/FM50-202-C.html

 

[StarCat]

Excellent Point

Excellent Point

Or because most likely the motors are the only 3 phase loads, separate out the motor circuits internally and install small VFDs on them, even though you will not vary the speed. 1-1/2HP VFDs capable of phase conversion will likely cost you less than $200 each. A little more tricky to do because it involves getting into the internal wiring, but in reality you should do that no matter what because you must make sure no controls are tapped off of the manufactured leg.

Example: http://www.factorymation.com/Products/FM50_230V/FM50-202-C.html

JRAEF excellent point.
I once inherited a small commercial laundry line at a facility I was handling. They were Milnor 3 phase machines. 2 the same and one of a later generation.
I deduced exactly as you say from failures and moved control circuit feed OFF of the phase generated leg which solved many problems instantly. All after replacing some burned items.
Machines were also running backwards which causes other issues, They are supposed to spin out a definite direction.
Interestingly enough also, the newer generation machine had to be converted to SINGLE phase input with an oversized VFD as SPEC'd by Milnor to solve its unique problems with PHASE GENERATED power. Some engineering depts. will have dealt with whats encountered in the field and work with you, but I'd say phase generation is to be approached carefully.

 

[iwire]

Or because most likely the motors are the only 3 phase loads, separate out the motor circuits internally and install small VFDs on them,

I would never even consider modifying the equipment unless I owned it.

These machines are expensive and I have no doubt the manufacturers would not honor any warranties after a knuckle dragging electrician got done ripping it open.

I have done 'slushie' machines that had tighter voltage specs than any other equipment I have touched.

 

[growler]

Or because most likely the motors are the only 3 phase loads, separate out the motor circuits internally and install small VFDs on them, even though you will not vary the speed. 1-1/2HP VFDs capable of phase conversion will likely cost you less than $200 each. A little more tricky to do because it involves getting into the internal wiring, but in reality you should do that no matter what because you must make sure no controls are tapped off of the manufactured leg.

I would never even consider modifying the equipment unless I owned it.

These machines are expensive and I have no doubt the manufacturers would not honor any warranties after a knuckle dragging electrician got done ripping it open.

I have done 'slushie' machines that had tighter voltage specs than any other equipment I have touched.

I'm not getting involved with rewiring these machines either.

Doesn't this get us back to the idea that if you only have single phase power the best option is a single phase machine.

There is a lot of this eqipment comming out of China these days I'm just not sure how long it last but the prices are good.

 

[Jraef]

I'm not getting involved with rewiring these machines either.

Doesn't this get us back to the idea that if you only have single phase power the best option is a single phase machine.

There is a lot of this eqipment comming out of China these days I'm just not sure how long it last but the prices are good.

Well, if they are going to void the warranty even though the line voltage is within normal specs. I'd say the users who buy them are hosed anyway.

A lot of this Chinese crap is sold by Fleabay resellers who disappear before any warranty claims can come in anyway, then the Chinese manufacturers disclaim any support responsibility requirements by saying they do not officially have marketing in the US, so it is up to the now non-existent resellers. I've seen that time and time again lately. The general concept of "Let the buyer beware" has somehow been lost on the buying public because of the attraction of impossibly low prices available at the click of a mouse.

 

[growler]

Or because most likely the motors are the only 3 phase loads, separate out the motor circuits internally and install small VFDs on them, even though you will not vary the speed.

Well, if they are going to void the warranty even though the line voltage is within normal specs. I'd say the users who buy them are hosed anyway.

I see that you work as a consultant and not as a contractor. It's very hard to hold a consultant liable for anything but as a contractor you are sticking your neck out when modifying equipment. Most of this type of equipment has a UL sticker and is really a commercial appliance.

I have modified equipment in years past and even with a written understanding that there was no warranty to void it was still risky. I was lucky and everything worked out .

 

[Jraef]

I see that you work as a consultant and not as a contractor. It's very hard to hold a consultant liable for anything but as a contractor you are sticking your neck out when modifying equipment. Most of this type of equipment has a UL sticker and is really a commercial appliance.

I have modified equipment in years past and even with a written understanding that there was no warranty to void it was still risky. I was lucky and everything worked out .

I was a contractor for years, also a systems integrator / panel builder. As a UL508 panel builder I took in many many machines from Europe and Asia to modify them to bring them up to US codes and UL listings. the issue often is that the end user has ALREADY bought the equipment and discovers too late that they cannot return it when they find out they cannot install it here, so in essence there is no warranty. UL is another issue however, you're right. If the machines are in fact UL listed, then even opening it up to modify the control circuit so that it does not come off of the phantom leg of a static or rotary phase converter will be an issue as well. There just is no easy way out.

Side note: in my previous post I said;

Well, if they are going to void the warranty even though the line voltage is within normal specs. I'd say the users who buy them are hosed anyway.

That was a mix-up on my part with a different thread (in a similar vein), sorry for any confusion that may have created.

 

[kwired]

I would never even consider modifying the equipment unless I owned it.

These machines are expensive and I have no doubt the manufacturers would not honor any warranties after a knuckle dragging electrician got done ripping it open.

I have done 'slushie' machines that had tighter voltage specs than any other equipment I have touched.

If it is new equipment, you should order what is needed for the location. If it is used equipment, you run into these type of problems sometimes - and there is no warranty left to void.

Pretty basic ice cream machines are around $10k last time I heard a price for one. If you small restaurant owner finds one for a couple thousand they are buying it and probably have no idea if their present electrical system can run it without changes. If they buy it for 2k and it is going cost 8K to make it work for them, they may as well sell it and buy a new one that will work and also has a warranty. Sometimes it is hard to convince some of these owners that is what would be best though.

 

[iwire]

Well, if they are going to void the warranty even though the line voltage is within normal specs. I'd say the users who buy them are hosed anyway.

The major difference is that if the owners of the machine make that call it does not come back on me.

Once I modify it, each and every problem they ever have with that machine will be looked at as my fault.

 

[iwire]

I was a contractor for years, also a systems integrator / panel builder. As a UL508 panel builder I took in many many machines from Europe and Asia to modify them to bring them up to US codes and UL listings.

Wow, I hope your arm is not to tired from all that.



We are not talking about bringing a machine up to listings we are talking about killing the listing due to modifications.

If the customer wants the correct power at the outlet I am there to do it. If they want the machine modified they are calling somebody else.

 

[Jraef]

Wow, I hope your arm is not to tired from all that.



We are not talking about bringing a machine up to listings we are talking about killing the listing due to modifications.

If the customer wants the correct power at the outlet I am there to do it. If they want the machine modified they are calling somebody else.

LOL, and I was the guy who would take that call... made a nice living off of it at the time. To each his own I guess.