Rotory pump and motors seem awfully big for the required water volume and torque to make 140 psi. Just out of curiousity. What is the smallest motor/rotary pump combo being used today? (Or are they all pretty much the same.)

not sure which is the smallest.. but I haven't seen a smaller rotary pump than the RPM in the middle..

The smallest rotary pump I have seen:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0322325427


Plus w/adjustable motor speed; seems a really good fit for espresso machines

HEY! Now that's cool

Has anyone tried installing one of these yet?

Hi guys,

I believe it's being run from the controller which is single phase but is able to power the 3-phase motor, as most VFD controllers do. The problem with simply going out, buying a VFD and sticking it to your existing pump motor is that they usually don't work with single phase motors with start capacitors.

I've noticed you can order an analogue board for it and run it through a 0-5V input (PWM or some other method). One thing I don't get though is how the speed affects the pressure, wouldn't that only slow down the pressure ramp up on the group? I mean if there's resistance pressure is going to raise anyway, or am I missing something?

Regards,
dsc.

http://www.fluidotech.com/Pages/en_fo_fa_30_200_literature.aspx
open PDF file: TMFR 0109 Ed.pdf
for dimensions and other specs.

Regards
Peter

One thing I don't get though is how the speed affects the pressure . . .

The TMFR, like all rotary vane pumps, is a positive displacement pump wherein flow is generally proportional to speed. The pressure in the system, as a result of this flow, is proportional to the square of the flow.

Greg S. has done an admirable job in applying this pump system in a commercial setting and that is a vast understatement - http://www.home-barista.com/espresso-ma ... 11113.html

However, keep in mind that this pump system is not YET ready for the home environment. The drive takes in 115-120 Vac and outputs ~ 90 Vac, 3-phase, variable frequency (30-120 Hz) to the pump/motor. The drive is (must be?) equipped with a filter card to meet UL requirements and this filter card is inherently not the "best of friends" with a GFI circuit in today's kitchens.

Other AC drives, more user friendly, are available on the market today - as an EXAMPLE - http://web4.automationdirect.com/adc/Ov ... 3947184022. Whether any of these other drives can be applied to the TMFR motor/pump is, at least, questionable. In addition to the link that Peter supplied for the Fluid-O-Tech site in Italy, the USA site has more info on the TMFR series: http://www.fluid-o-tech.com/

erics wrote:The drive is (must be?) equipped with a filter card to meet UL requirements and this filter card is inherently not the "best of friends" with a GFI circuit in today's kitchens.

If I understand GFI correctly and translate the Dutch name for it into English words, then it would be called "earth leak switch" - standard in our houses for decades.
I do not understand the "filter card", what does it do?

As to size, I think the TMFR motor/pump is pretty small and the attraction is it has no moving parts other than the pump. The "motor" magnetically pushes the magnet in the pump around without rotating an axle. No coupling, no additional vibes.
The control box is a bit smaller than the motor/pump. What about other motors that are used in espresso machines - do they all require some control/drive unit? What is the rationale here?

Regards
Peter

A few years ago I was looking for a motor/pump as compact as possible and back then stumbled on several models by Procon.
I recorded some data on the MagDrive Series 2 & 3, 5, 6 and Canned Motor Pump (CMP) 7000, all quoted as suited for espresso machine usage. [http://www.proconpumps.com]
IIRC these were significantly smaller than a motor/coupling/pump package.

Regards
Peter

Now this is getting a little beyond my pay grade so take with a pinch of espresso.

Part of the TMFR drive unit is an inverter and inverters tend to create electro-magnetic interference (EMI). So if your "significant other" happens to be watching the daily soaps on TV and you are busy brewing espresso with your TMFR equipped machine, you are very likely to be shown the way to the dog house for the electrical interference you just caused at the most inopportune moment. Hence the need for a filter card to "filter out" this EMI.

Now, filter cards inherently leak a little current to ground and, depending upon the sensitivity of your GFI outlet, you may experience some brewing difficulties

What is the rationale here?

I BELIEVE the initial rationale was to duplicate the attributes of a spring-lever machine but that has been expanded to include more user control over the espresso brewing process. If you read Greg S's posts on pressure profiling, you will have a more thorough grasp of what he is intending - not that you don't already have some ideas.

erics wrote:inverters tend to create electro-magnetic interference (EMI).

You imply the EMI is put on the electrical grid, but would it also be broadcast?

erics wrote:if your "significant other" happens to be watching the daily soaps on TV

As we do not have TV, I would be worried also about air-borne EMI/RFI that is received by my audio (0-MHz bandwidth).

erics wrote:Now, filter cards inherently leak a little current to ground

Thinking out of the box here. Thinking of my vacuum cleaner (Electrolux), 1600W electrical power with a GE turbine of 425W suction. If you were to switch on its 1600W motor, knowing an electric motor has 0 Ohm internal resistance initially, then you know an infinite current will flow when switching it on without any control device. So what did the nice vac sucker people do? Add in a circuit that slowly revs up the motor. Plus they put a UI on it for me the user to be able to reduce suction if/where necessary.
Back to EMI. This thing is very silent electrically as perceived by my stereo. (No I do not use AC filtering or re-genration or AC wave synthesis à la PSAudio.)
I just do not know if the motor is 1 or 3 phase. Probably 1 (no inverter then?). And the big dust sucker has no ground connection. Part or all of our required solution apparently is out there.
Now here I get back to my question:

CafSuperCharged wrote:What about other motors that are used in espresso machines - do they all require some control/drive unit? What is the rationale here?

I understood the espresso related rationale, however my reasoning is based on the physics knowledge of a 14 year old grammar school pupil of about 42 years ago.
What is the rationale of controlling electrical motors other than the one I described above?

Regards
Peter

I think it is a brushless DC type motor and a controller is required to run it. The motors are very efficient and can be sealed to keep out coffee grinds. They cost a lot more then typical AC motors other wise we would see alot more of them.

Hi guys,

I also think it's a DC motor* and I'm quite convinced it's controlled with PWM, that's why you need that black box to run it. Without it you would have to connect it to a DC power supply and you'd only get one speed (3500RPM).

Would be nice to get a DC motor to run an ordinary rotary pump, it could be easily controlled to get various speeds/pressures. Does FOT sell motors as well?

Regards,
dsc.

*EDIT: nope it's an AC motor, the controller is there simply acting as VFD.

CafSuperCharged wrote:You imply the EMI is put on the electrical grid, but would it also be broadcast?

One pretty much implies the other. Any waveform with sharp transitions (square waves or spikes) has a large high-frequency component, which tends to radiate from pretty much anything. Including power lines.

A traditional homebrew amateur radio builder's complaint was that it too often seemed easier to get the signal to the power lines than the antenna!

Hi guys,

anyone tried or thought of using this instead:

http://fluid-o-tech.com/files/Mg.pdf

??

the flow ratings are significantly lower.

Regards,
dsc.