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:
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
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
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.