Hi there!

I am trying to understand what is the type of circuit required to drive a 240V AC electromagnetic vibrator feeder, I have inspected a circuit of an existing speed controller that I had laying around and seems to be using a BTA16 triac. My original idea was to reverse engineer the circuit although I would prefer first to identify the name or the type of circuit required to understand how the vibrator is controlled.

I have tried to search for such circuit without any luck as I mostly stumble upon AC motor speed control circuits.

If anyone has any circuit that I could look at or could point me in the right direct it would be greatly appreciated, I am not looking for anything fancy, a simple control circuit with a potentiometer will be great.

The vibrator in question is similar to the one in the picture below.

 

Is this an application where you could use 50hz/60hz?
If so a simple AC level/supply fed from the local AC power.
Is the reason for the Triac to regulate rate of vibration?
If so a simple phase angle control circuit would work.

 

I mostly stumble upon AC motor speed control circuits.

If the answers to Max's questions are yes, than such a controller should work for you.

 

According to this article it is the vibration frequency, rather than the amplitude, which needs to be controlled. That rules out simple 'lamp-dimmer' style phase-angle contol.

 

agreed...

on the other hand, i just glanced that article and there are some obvious mistakes there.
for example just the zero cross detector on 220V mains uses optocoupler with 680 Ohm resistor.
why would 4N35 input need more than 300mA? and the resistor would dissipate more than 70W.
then the output of the optocoupler connects 5V to the base of NPN transistor without any current limiting.

 

This may seem a bit obvious, but does the bin vibrator manufacturer provide any information about voltage and currents required to drive their products??
Really, an "H-Bridge" circuit fed by a n oscillator with a square wave output and powered by rectified mains voltage should be adequate. Of course probably a 25% duty cycle would be better than 50%.

 

I am trying to understand what is the type of circuit required to drive a 240V AC electromagnetic vibrator feeder,
The vibrator in question is similar to the one in the picture .

What is the purpose you are putting them to ? And what is the details on the item label state?
If you can get away with mains freq. This will be the cheapest method, they do not appear to be high freq devices?

 

vibratory feeders use mechanical vibrations/oscillations that are supported by springs. triggering and releasing spring results in decaying oscillations. this triggering of vibrations is excited by an electromagnet that is pulsed at some adjustable intervals. typical bowl feeder uses pair of such axis that are perpendicular to each other. this allows creating mechanical version of Lissajous curve. mechanical vibrations then make parts oscillate. the continuous pulse train keeps the parts moving. when parts are packed densely, this is maximized as they all push on each other, resulting in net motion. path is typically a spiral so that parts gradually climb up. using custom profiles it is possible to reject parts with wrong orientation - they are simply allowed fall back into the bowl and eventually will come out in correct orientation. oscillation frequency is usually in range of some 5-30Hz.

the other way to create vibrations is to use motor with excentre weight and adjustable speed. normally those are purpose built units with bearings that are rated for such operation. I have used both, usually in automotive... bowl feeders are commonly used to move material. they are loud and create a lot of rattling noise. vibrations created using motors with excenter weights are quiet and suitable for testing that involves collecting data.

 

..And one example of a 50hz/60hz vibrator action is the typical tap buster, where a mains freq coil is used, with no shading ring or other dampening , it results it quite a heavy vibration.