Slowing down a Santos Mixer

[Pizza Napoletana]

Along with being dangerous a variac WILL NOT WORK AT ALL with the type of motor in your santos and a transformer will not slow it down enough.

Omid! Mr. Fouquet is reading this post and he will try to do something about this ,he is a very nice man and passionnate
so hope for the best in the future!

A power inverter takes DC power(most commonly 12 volt) and converts it to AC power by generating it's own wave form.  Here in the US a power inverter would produce 60hz power to feed standard US products.  In Europe a power inverter would produce 50hz power to feed their standard products.  A rectifier converts AC power to DC power.  So if you take your 120V 60hz American power and feed it into a rectifier producing 12V DC power, you can then feed that 12V DC power into a European power inverter which will produce 50hz AC power.  Obviously you would need to convert the European plug on the inverter to an American plug, but thats no big deal.

To take this a step further, you could modify the inverter to produce whatever frequency, and hence whatever RPM you desire.  The frequency of the wave produced by a power inverter is generally controlled by one resistor.  Change the value of that resistor and you change the frequency of output.  This exact method is used in some variable frequency drives by using a variable resistor of some sort in the circuit, but since you want a fixed RPM a fixed resistor would work.  Here is a link that discusses doing exactly this to controll motor speed for a different purpose:

http://bobmay.astronomy.net/misc/drivcorr.htm

If anyone tackles this read the warnings in the link, and remember power is dangerous.  A fraction of a Milli Amp can kill you in the right situation, so know what you are doing before you proceed.

Just realized I forgot the transformer.  You first need a 12v transformer to produce 12v ac.  Then a rectifier for 12v dc.

The inverter has to be large enough to handle the start surge current. The 2000 watt inverter is 3 times the running wattage to handle the start. Also, is the $85 inverter on Amazon 50 HZ @ 120 volts ?  I'll bet it isn't a pure sine wave supply. I think the pure sine wave design is part of the high cost.

Dear friends, I thank all of you for your contributions toward solving this issue. it seems to me that some of us involved in this Santos-fork-speed project hold  pieces of the puzzle! Moreover, per my research, it appears that Mr. Scott_r and some other respectful individuals are right about futility of Variac, which merely increase or decrease the voltage. With my very limited knowledge of electronics, today I spent about four hours of research, trying to have some rudimentary understanding in respect to the electronic principles underlying armature speed. The followings are the tentative results of my research.

1. According to the identification plate attached to the bottom of my Santos mixer, the following are the specifications of the mixer:

Santos Mixer Type: 18V1
100-120 Volts
50/60 Hz [Frequency]
650 W [Wattage]
4.5 A [Amperage???]
1800 tr/min [translation: tours par minute or "turns per minute" (which translates to the fork speed of about 84 RPM at 60 Hz)]

2. According to the manual that came with my Santos mixer (type 18V1), its electronic motor is run by alternating currents (AC). Further, its motor or armature is  a "single phase asynchronous [or 'induction'] motor".

3. It seems that the single-phase asynchronous motor of Santos generates a rotating magnetic field by using one of the following methods:

    (a) "Capacitor start motor", which is a type of "Split-phase induction motor" that is commonly used in home appliances such as washing machines, clothes dryers, fans, and etc. A "capacitor start motor" is equipped with a starting capacitor inserted in series with the startup winding, creating an LC circuit which is capable of a much greater phase shift and, hence, a much greater starting torque.
    (b) "Permanent-split capacitor motor" aka "capacitor start and run motor" which is commonly used in air blowers, ceiling fans, and other cases where a variable speed is desired.

4. Assuming that the Santos mixer uses the "capacitor start motor" (method "a") for generating a rotating magnetic field within its armature, the speed of the motor is primarily controlled by the "number of pole pairs" and the "frequency" of the supply voltage. In other words, it appears that the motor's RPM (rotations per minute) is primarily determined by two factors: (1) the number of poles in the stator winding, and (2) the frequency of the AC supply.

I do not believe changing the "number of poles in the stator winding" is a viable option, which consists in physically modifying it, if possible at all. However, I presume I can manage to change the "frequency" from 60 Hz to 50 Hz while maintaining a voltage of 100-120 volts. And, to accomplish that one needs a specialized converter, that can be quite expensive. One such device is "APT VariPLUS MODEL 105", which is probably an overkill. Luckily, I have found someone in San Diego who is willing to sell his VariPLUS to me for $300.00. (The retail price is about $995.00.) At this point, I do not know if this is a safe, sound, and effective solution. I will know more about the device tomorrow. You can check out the following link and youtube videos in regard to the VariPLUS MODEL 105 below.

http://www.aspowertechnologies.com/products/VariPLUS/VariPLUS105.aspx

<a href="http://www.youtube.com/watch?v=JmnclNntwm0&amp;feature=player_embedded" target="_blank" class="aeva_link bbc_link new_win">http://www.youtube.com/watch?v=JmnclNntwm0&amp;feature=player_embedded</a>

<a href="http://www.youtube.com/watch?v=cVHgAwPCCio&amp;feature=related" target="_blank" class="aeva_link bbc_link new_win">http://www.youtube.com/watch?v=cVHgAwPCCio&amp;feature=related</a>

<a href="http://www.youtube.com/watch?v=IbrK1Q58AtI&amp;feature=channel_video_title" target="_blank" class="aeva_link bbc_link new_win">http://www.youtube.com/watch?v=IbrK1Q58AtI&amp;feature=channel_video_title</a>

After all said and done, I am afraid that running the mixer at 50 Hz may not reduce the RPM low enough. According to the Santos manual, the motor speed at 50 Hz is 1450 RPM, which generates a fork speed of 70 RPM. This speed is not slow enough! I need a fork speed lower than, or at least, 45 RPM. Many prominent Italian fork mixers run below 45 RPM.

[apizza]

The quick spec for this unit says 4.6 amps max. Bill/SFNM's Santos plate says 4.5 amps.  Much too close for me, and will it handle the start surge of the Santos motor?

[holorim]

Hello,
When I owned a 18 mixer (many years ago), I managed to change the speed quite easily.
Its single phase motor was fitted with a permanent capacitor (instead of a starting capacitor which is disconnected since the rotor began to run), and this allowed me to drive it via a frequency inverter.
But be carferul to not choose any model : theses devices are first of all made for 3 phase induction motors, but fews models are able to drive single phase motor which do not have transitional state when starting (i.e permanent capacitor)...

If the variable speed is not required, another solution would consist to replace de worm&wheel gears located inside the reducer. These gears are made of brass, and I suppose that any milling shop would be able to copy these gears but with a bigger reduction ratio.

Regards.

[Pizza Napoletana]

The quick spec for this unit says 4.6 amps max. Bill/SFNM's Santos plate says 4.5 amps.  Much too close for me, and will it handle the start surge of the Santos motor?

Dear Apizza, I do not know if the VariPlus Model 105 handles the start surge of the Santos motor. If the "start surge" is the same as "inrush current", the specifications below may hold an answer to your question. Good day!

<a href="http://www.youtube.com/watch?v=IbrK1Q58AtI&amp;feature=channel_video_title" target="_blank" class="aeva_link bbc_link new_win">http://www.youtube.com/watch?v=IbrK1Q58AtI&amp;feature=channel_video_title</a>

[Pizza Napoletana]

Hello,
When I owned a 18 mixer (many years ago), I managed to change the speed quite easily.
Its single phase motor was fitted with a permanent capacitor (instead of a starting capacitor which is disconnected since the rotor began to run), and this allowed me to drive it via a frequency inverter.
But be carferul to not choose any model : theses devices are first of all made for 3 phase induction motors, but fews models are able to drive single phase motor which do not have transitional state when starting (i.e permanent capacitor)...

If the variable speed is not required, another solution would consist to replace de worm&wheel gears located inside the reducer. These gears are made of brass, and I suppose that any milling shop would be able to copy these gears but with a bigger reduction ratio.

Dear Holorim, I thank you very much for your comments! Please, allow me to ask you a question. When you say "18 mixer", do you mean "Santos Mixer Model 18"? I will keep the "permanent capacitor" and "worm&wheel gears" in mind when I soon see a local armature specialist.

I talked to one such specialist over the phone today. Not having seen the motor in person, he suspected that the santos' single-phase, asynchronous/induction, capacitor-start motor has "four poles". And, he stated by adding four more poles, if possible, he can reduce the speed from 1800 RPM to 900 RPM, at the cost of over $1000.00 and possibly $3,000 dollars!

Not knowing anything about the Santos company, I would be too presumptuous in thinking that: the high price of designing a new motor leads me to speculate that perhaps when Santos decided to market the mixer here in the US, they introduced the old motor in the new market, rather than designing a new motor to fit the circumstances of the new market. Good night and thank you again!

Respectfully,
Omid

[Pizza Napoletana]

Another local electric motor specialist just called me and told me the same thing as above. Price? "Possibly over $2,500 dollars". At this point, I am quite agitated. It is time to listen to the melancholic voice of Maria Callas to calm me down!

[apizza]

I'm going to guess the Variplus at 18 amps in rush will handle the start, but here is the real problem.

"After all said and done, I am afraid that running the mixer at 50 Hz may not reduce the RPM low enough. According to the Santos manual, the motor speed at 50 Hz is 1450 RPM, which generates a fork speed of 70 RPM. This speed is not slow enough! I need a fork speed lower than, or at least, 45 RPM. Many prominent Italian fork mixers run below 45 RPM"

So I wonder if you should put money into something that will not give the desired result. Perhaps this thread will produce a solution. I'm still thinking about it. An interesting problem.

[holorim]

Hi Omid,
Yes I was talking about de Santos Mixer model 18, as you illustrated it with the exploded views above.
Originally this brand was specialized in electric motors, but since it totally becomed a manufacturer in food machines, now the motors are contracted out (mainly the Société des Moteurs Electriques de Normandie).
I can confirm you the motor is 4 poles (synchronous speed = 1800 rpm at 60Hz). Rewind it with 6 poles would reduce the synchronous speed at 1200rpm (and 900 with 8 poles), but unfortunalety this operation will be uncertain on a single-phase motor which is always engineered for only one optimal winding.
In my opinion, its better to keep the actual motor, and to power it with a 3-phase inverter which can drive single-phase motor (i.e. Siemens Micromaster's range).

[Pizza Napoletana]

I'm going to guess the Variplus at 18 amps in rush will handle the start, but here is the real problem.

"After all said and done, I am afraid that running the mixer at 50 Hz may not reduce the RPM low enough. According to the Santos manual, the motor speed at 50 Hz is 1450 RPM, which generates a fork speed of 70 RPM. This speed is not slow enough! I need a fork speed lower than, or at least, 45 RPM. Many prominent Italian fork mixers run below 45 RPM"

So I wonder if you should put money into something that will not give the desired result. Perhaps this thread will produce a solution. I'm still thinking about it. An interesting problem.

Dear Apizza, you are quite right! That is exactly the thought I have been entertaining all day. I truly hope that the Santos makers TAKE NOTICE of all these posts we have been posting here. Yet, I still wonder how he did this:

<a href="http://www.youtube.com/watch?v=p9lU843ATI0&amp;feature=related" target="_blank" class="aeva_link bbc_link new_win">http://www.youtube.com/watch?v=p9lU843ATI0&amp;feature=related</a>

. Are we miscalculating or not fully examining our assumptions?

[Pizza Napoletana]

Hi Omid,
Yes I was talking about de Santos Mixer model 18, as you illustrated it with the exploded views above.
Originally this brand was specialized in electric motors, but since it totally becomed a manufacturer in food machines, now the motors are contracted out (mainly the Société des Moteurs Electriques de Normandie).
I can confirm you the motor is 4 poles (synchronous speed = 1800 rpm at 60Hz). Rewind it with 6 poles would reduce the synchronous speed at 1200rpm (and 900 with 8 poles), but unfortunalety this operation will be uncertain on a single-phase motor which is always engineered for only one optimal winding.
In my opinion, its better to keep the actual motor, and to power it with a 3-phase inverter which can drive single-phase motor (i.e. Siemens Micromaster's range).

Dear Holorim, again, I thank you for heartening me!

[Pizza Napoletana]

I can confirm you the motor is 4 poles (synchronous speed = 1800 rpm at 60Hz).

Dear Holorim, according to the page 2 of the Santos manual (http://www.santos.fr/Doc_com/EN_English/SANTOS_18_leaflet_EN.pdf), the motor is a "single phase asynchronous motor". I do not know if this makes difference in regard to diminishing the fork speed. Bonne nuit!

[Jet_deck]

As a Southerner with a "degree" in Southern Engineering, I propose five suggestions.

1) Double the diameter of the bowl.  I know this does not help the smaller batches, but it decreases the kneading action by half.

2) Cut off 1/3 the length of the mixing arms. Hacksaw blades are very cheap and require very little skill to operate.

3) Bend the forks so they do not contact the bowl so aggressively.  

4) Offset the center of the bowl rotation, so that the forks do not contact the bowl so closely.

5) Decrease the diameter of the forks, so that they do not contact the bowl so aggressively.

See y'all later...

[holorim]

@Pizza Napoletana : the inverter doesn't control directly the motor RPM, but produces a current with an adjustable frenquency ; but on an induction motor the frenquency affects the RPM, which is the same goal indeed.
All inverters are able to yield from 0Hz to 60Hz (and many more but it doesn't recommended to overspeed a motor which isn't designed for) : then you may be able to adjust the motor at the speed you want, from 0 up to 1600 RPM with an accuracy of a couple of RPMs.

[scott r]

omid, the youtube pietrosantos was modified with a new motor and a variable frequency drive.  The new motor was attached to the side.  the motor and vfd were only a few hundred dollars, but you need access to a metal shop that can either lathe down the end of the new motor to fit in the santos drive shaft, or have them make a small adaptor to mate the new motor with the drive shaft in the santos.  I have the details on how to do this, and manufacturers for the vfd and motor used in the video, so feel free to email me if you are interested in going for this.     I think the metal work would only take a few hours at most, so the cost would likely be under 500 for the full modification and parts.   Hopefully santos will some day come out with a unit that does this on its own (without modification).  

[scpizza]

the youtube pietrosantos was modified with a new motor....The new motor was attached to the side.

Nope, that's a physically unmodified, stock Santos running on the factory motor.  There is no chicanery like a hidden motor bolted on to the side.

[apizza]

Nope, that's a physically unmodified, stock Santos running on the factory motor.  There is no chicanery like a hidden motor bolted on to the side.

If so do you know how the speed was reduced?  I can only guess it was a variable frequency drive, or a new gearbox was manufactured.

[Zeppi]

I truly hope that the Santos makers TAKE NOTICE of all these posts we have been posting here.

Omid , Mr Fouquet said that it will take a few months for him
to rethink and find a solution for a slower speed so hold on!


Louis

[Jet_deck]

Nope, that's a physically unmodified, stock Santos running on the factory motor.  There is no chicanery like a hidden motor bolted on to the side.

So what is the big deal with just telling him how you did it? Or does it cost money for you to tell how you did it?

[scpizza]

So what is the big deal with just telling him how you did it? Or does it cost money for you to tell how you did it?

Yes, it could cost me everything I own.  Under the U.S. legal system people will go off and hurt themselves then blame and sue someone else who was just trying to help.  No good deed goes unpunished.

I only spoke up to help you good people from going down the rat hole of trying to bolt on an exterior motor (been there, tried that).  Can't say that I appreciate the hostile comment in return.  No good deed goes unpunished, indeed.

[scott r]

Nope, that's a physically unmodified, stock Santos running on the factory motor.  There is no chicanery like a hidden motor bolted on to the side.

aah, well it looks like you changed your plans after we talked.    Sounds like you must have bypassed the capacitor for everything but the startup allowing the use of the vfd?     I wish you had told me that works, or I wouldn't have sold my santos!  This whole time I thought the curtain was there covering up the new motor and vfd.   oh well, im glad you got it going, it must be amazing having that thing going at the right speed!