A (Epic?) journey in search of my perfect roaster

[Javaphile]

Re: A (Epic?) journey in search of my perfect roas

LOL I kinda fall into both camps. I not only love to tinker with the rebuilding, I also love to use the equipment. I get to tinker with it even more that way! ;D

Theres nothing in this restoration/rebuild that I couldnt do given the neccessary equipment. From the construction of a new box (straight forward geometry and basic sheetmetal working abilities) too stripping and plating the existing box (I used to work in the R&D lab at the worlds foremost high-end PCB manufacturer where we plated using everything from copper, to nickle, to gold).

Unfortunately I no longer have access to their 5,000 gallon stripping and plating tanks, nor to a sheetmetal shop or sandblaster so Im relegated to paying for these services. :-/

As many tools and devices as I have I dont have them all....D*mnit!

Im still hoping to be able to start testing the roaster by next week-end.

The current plan is to take the roaster up to the Sodablaster on Monday and hell do it while I wait. When I get home Ill then paint the inside of the flame chambers. Then while the paint sets up and cures Ill be working on getting the motor operational which may be as simple as dropping one of the 3-phase legs off and running it on 220 single phase. From the sounds of it Id end up with a motor turning at 1700 rpms instead of 1400 with a third less power and that would prolly need a hand getting started.

This may or may not work. I wont know until I try it. The power of the motor I think is more than needed and if they ran it as it appears with no oil on the barrel shafts properly lubricated it will most likely require half as much energy to keep it all turning once up too speed. Given the already high rpms of the barrels (Gothots traditionally ran at about 60 rpms) the added rotation may not have much of an effect on the roast. The additional speed of the turbine wont matter as the air flow is adjustable on each barrel independant of the turbine.

So at this point the determining factor looks to be the curing time of the paint. What that is I dont know yet as Ive not bought it.

Java "Onward and upward!" phile

[robusto]

Re: A (Epic?) journey in search of my perfect roas

If the motor is an induction one ( they have a huge barrel capacitor usually within a housing on top) there may NOT be enough single phase power to overcome inertia and get it going. But if its a good ole fashioned brushes type, that may not be a problemo.

I suppose the upside of it all is you have something built like a tank -- built to last, but a little on the difficult side to unravel to its components.

A bit off topic here, but everytime I see that show, Mythbusters, I drool. What a toy-building factory those guys have! Never having to stand back and ponder how the hell they are going to build a super-cyclone turbo- widget. Because they KNOW they have the tools and raw materials to do it, and everything else. Thats what I call a garage, folks.

[Javaphile]

Re: A (Epic?) journey in search of my perfect roas

Theres no caps on this motor at all. None are needed Ive been told as its a 3-phase and as such has enough power to self-start. Its a standard brushless AC motor.

The big power draw will be getting up too speed. Once up too speed the power draw should drop enormously, especially when its properly lubricated!!

Im hoping that by manually spinning the larger pully wheel as the motor starts that it will then be able to get up too speed and hold it with-out a huge current draw.

I have huge (4,500kg) printing presses here that are powered by a 1/4hp motor. The motor on the roaster appears to be a 3/4hp one. Even with a third of its power gone it still has 1/2hp which I will be rather surprised if it isnt enough to run the roaster once its up too speed.

The only question is can I wire it for single phase 220, and can it be done with-out the two legs being too unbalanced. If that can be done then the question becomes one of will it have enough power to get up too speed. I wont be able to spin the larger pulley wheel but for part-way to its proper speed. At a rough guess the larger wheel will be making between 2 and 3 revolutions per second when at operating speed.

I LOVE Mythbusters!! How can anyone *not lile it? I mean cmon! They blow something up every show! LOL

Java "Dreaming of B&Gs!" phile

[Dimal]

Re: A (Epic?) journey in search of my perfect roas

Hi Java,

Alas, it is not as simple a matter as it sounds to run a 3-Phase motor on a 1-Phase supply. If you do want to try it with one "leg" taped up, you will need to setup some kind of device to set the motor to spinning before you energise it, as it will NOT start by itself with the 3rd leg missing (sounds a bit like an aged diabetic Jake the Peg doesnt it ).

Depending on access to the motor shaft or some part of it, it can be as simple as using a pull-cord to spin-up the motor then hit the start button. As to the power output of the motor in this configuration, youll only get about half the nameplate rating from it, not two-thirds as you have surmised. It comes down to a vector sum of the voltage and current components actually, not a direct sum :-?.

As to hitting the motor with a 220 Volt single phase supply voltage... this is not a good idea unless youve got some BBQ Ribs or some such that you want to cook in a hurry . The motor will draw way too much current and burn the windings out in pretty short time. Hope this helps out a bit and maybe avoids setting fire to your roaster in a way you havent planned on .

All the best,
Mal.

[Javaphile]

Re: A (Epic?) journey in search of my perfect roas

Hhhmmmm.....More food for thought Mal. :-/

The roaster is all loaded up in the van and ready for its trip to the Sodablasters tomorrow.

If all goes smoothly in 24 hours it will be blasted clean and repainted in those areas requiring it.

Java "The ever hopeful" phile

[Javaphile]

Re: A (Epic?) journey in search of my perfect roas

The more I think about this the more it seems the simpliest and easiest thing to do would be to get a Frequency Inverter such as this one: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7521080659 (technical specs here: http://actechdrives.com/scm_data.htm )

That would resolve all the problems with the power supply for the motor and allow me to control the speed of it as well.

I had originally discounted going this route due to the high cost. Upon looking into it further though it can be done for dramatically less than the $500USD Id been told.

Now the only question in my mind is if they can be used with my motor as Ive seen many references saying that theyre designed for variable speed motors and this one is not designated as a variable speed motor. My thoughts on it are that if nothing else I can use this device to convert my single phase too 3-phase and to drop the frequency from the 60Hz supplied here to the 50Hz the motor was made for.

I also see that this unit does not have a 220v output but it does output 230v. From all Ive heard my motor should be able to take 230v.

Any thoughts on this Mal? Anybody?

Java "Head spinning round and round" phile

[robusto]

Re: A (Epic?) journey in search of my perfect roas

Would it not be cheaper, easier, to get a new/second-hand motor? Or are there problems with the mounting and shaft...

Life was not meant to be easy, or cheap.

[Javaphile]

Re: A (Epic?) journey in search of my perfect roas

Would it not be cheaper, easier, to get a new/second-hand motor? Or are there problems with the mounting and shaft...

Life was not meant to be easy, or cheap.

The motors shaft fits inside of the drive shaft for the turbine blades and as such it must be an exact fit or the turbine will be off-center and quickly destroy the motors bearings given the rpms its spinning at.

Ive measured the motors shaft at .470" which is halfway between 15/32" and 12mm. A 15/32" shaft is not a stock size but a 12mm shaft is available as a stock item but it may need to be turned down a few thousandths of an inch to fit into the turbines shaft. Then it would also have to have a set screw indentation drilled into it at the appropriate location so that the turbine shaft can be locked to it properly.

Once that is done then the motor would need to be mounted on a base so that its shaft lines up properly with the turbine housing. Due to its age and European manufacture this would most likely require a custom bracket.

Once all that has been done the higher speed of the new/used single phase motor would still need to be dealt with.

The current motor (made for Mexicos 50Hz electrical supply) runs at 1420 rpm while a 60Hz (what is used on the USs grid) motor will run at about 1,700 rpms.

Looking at new motor prices a 3/4 too 1 HP single phase motor will run almost $200, the same price as the frequency inverter, and would still need another $50-$100 in modifications to be usable *plus the cost of a speed controller for it. Which is guess what, yup, a frequency inverter. it would be cheaper than the one I referred too in the previous posting as it wouldnt need to have the phase converter in it but would still run about $75-$100.

All-in-all its cheaper and easier to buy a frequency inverter with a built-in phase converter.

As well as being cheaper and easier it also leaves the original motor intact and untouched. Always a good thing when dealing with a collectible. Anytime you modify or remove an original part the value of the item as a collectible goes down, sometimes quite dramatically. Seeing as there are only a handful of these roasters left in the world it would probably behoove me to keep it as original as possible. Yet another collectible to pass on to the kid when the time comes. ;D

Java "Sometimes its hard being a tinkerer as well as a collector" phile

[robusto]

Re: A (Epic?) journey in search of my perfect roas

Gulp. Sorry I asked. :-/ Ive been nursing an air conditioning/heating motor and squirrel cage fan assembly for years. The set screw was never tightened properly and after a while the cage started spinning freely around the motor shaft. It wore down the shaft unevenly while enlarging its own hole. The eccentricity shakes the heater mercilessly and I dread to think what the neighbours say about the noise.

The experts said no problem. Cant be fixed, so new motor and fan = $600.

I dont believe in throwing out a motor while it fulfils its essential function to spin, which it does, even with a poor excuse for a shaft.

So, remove, re-weld remove and re-weld the very heavy assembly so many times over almost 2 decades when the vibration becomes intolerable.

But sometimes, just sometimes.... I envy those guys who see/hear something is amiss, call in an expert, and part with wads of cash without getting their fingers dirty.

[Javaphile]

Re: A (Epic?) journey in search of my perfect roas

But sometimes, just sometimes.... I envy those guys who see/hear something is amiss, call in an expert, and part with wads of cash without getting their fingers dirty.

I hear ya. It would be nice if we were all so well off that we could afford to throw around that kind of money with-out a second thought.

Theres very few things Ill farm out around here. Repairs to the car being the only thing that comes to mind.

I hired out the complete replacement of the exterior of my house a few years back (roof, windows, siding, sofits, facia, trim, the *entire exterior) but that was only because Id taken major damage to the house in a huge storm (3-4cm hail and 120kph winds) and got a big chunk from my insurance company and used that to leverage some matching funds from a community reinvestment company (both of them required a licensed contractor to do the work) which gave me enough (after 3 years of shopping around and being my own general contractor) to pay contractors to do the work.

When I built my basement addition to hold my presses I contracted out the foundation work but did the rest of the construction myself. Ive completely rewired the house right from the masthead in with the removal of *all the existing wiring (4 generations dating back over 100 years to the original knob-and-post), and have just recently completed a complete replacement of all the plumbing in the house.

The current work on the kitchen Id do myself as well but because its an insurance claim the cost to me is the same whether I do the work myself or have a contractor do it, the $500 deductable. So I think in this case Ill let them do the work. ;D

Java "Repairs R Us" phile

[Javaphile]

Re: A (Epic?) journey in search of my perfect roas

Ugh! The bad news of the day: No blasting of the roaster today. A half hour before I was scheduled to take it in to be blasted my sewer main decided it was time to back up! >

Ive rescheduled the blasting for tomorrow and currently have a rooter on the way over to clear the line.

Java "Sheesh, what next?!" phile

[robusto]

Re: A (Epic?) journey in search of my perfect roas

Well, your disappointment is ours, too, if thats consolation. We wait with baited breath for the next instalment of this internet saga/epic. I know its the talking point around my household --no, no, dont be unkind, we DO have a life.

....Wonder it thats the case multiplied by a couple of hundred coffeesnobs, their partners, aunts and just plain acquantances.

[Andy]

Re: A (Epic?) journey in search of my perfect roas

....Wonder it thats the case multiplied by a couple of hundred coffeesnobs, their partners, aunts and just plain acquantances.

I have to sheepishly raise a hand too ;D
Guilty as charged sir.

[wattgn]

Re: A (Epic?) journey in search of my perfect roas

Jeez poor Java in the shit again phile.

Very bad luck.

Maybe a plague of locusts next?

Grant

[Dimal]

Re: A (Epic?) journey in search of my perfect roas

The more I think about this the more it seems the simpliest and easiest thing to do would be to get a Frequency Inverter such as this one: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7521080659 (technical specs here: http://actechdrives.com/scm_data.htm )

I also see that this unit does not have a 220v output but it does output 230v. From all Ive heard my motor should be able to take 230v.

Any thoughts on this Mal? Anybody?

Java "Head spinning round and round" phile

Hi Java,

Yep, an Inverter is one way to solve the problem. You just need to match the Input and Output characteristics to suit your particular circumstances. I thought your motor was rated at 127 V/Phase though, not 220V?

Have had a look through the Specs of the unit you linked to above and there is a good chance that one of these will do the job. You would need to talk to some tech people there though, to make sure that these units are suitable for running continuously at 127 Volts Output with your particular motor.

Another option to think about is a "Soft Starter". These are similar to Variable Speed Inverter Drives but without the variable speed. Getting one that provides a 127-130 Volt output might be tricky though.

Something else you need to be aware of with Inverter Drives, is that they are extremely electrically noisy, i.e. they introduce a wide range of RF, Transient and Phase Shift noise into the local electrical grid. Given that you will only be using a small one, the range of this noise will be limited but might be severe enough to impact on other electrical and electronic equipment in the house. In order to reduce the significance of this noise, it would be a good idea to install a recommended filter network at the immediate "upstream" side of the Inverters installation point.

Just going back to your motor.... it sounds like it is a very special little motor and probably difficult to find an equivalent replacement as a 1-Phase unit, given that it has a special output coupling arrangement and probably an over-sized bearing to take care of the significant loadings involved. Rewinding the motor as a single phase unit would still be worth chasing up though and should be way cheaper and simpler than using an Inverter or Soft Starter. I wouldnt discount this option Java as it should be possible to rewind it as 1-Phase, Capacitor Start unit with a permanently connected and rated Capacitor. A motor rewinder would be able to sort this out for you and may even do it for a very attractive price if certain coffee orientated inducements are offered... worth a try .

Hope something works out for you,

Mal.