vibrating conveyors?

[pmac10]

right, i've never come across one of these until a breakdown situation tonight in my new place of employment and got a sketchy idea of whats supposed to happen from the line technician and my new fitter pal.i managed to work out an optical sensor above the conveyor detects a lack of product which signals a 'vibration controller?' to on which outputs to two sets of two, what i think are coils, with unfixed points of the conveyor between them and vibration begins. managed to sort the problem by increasing the amplitude on the controller (the line technician whose been doing this for years was on the wrong parameter), but there are a few of these machines in site and i'd like a better understanding for the future, especially how the controller operates, is it alternatively pulsing the coils at high frequency or what?
over to you, Tony/Silva/E54/NBP and anyone else i may have missed.

 

[Knobhead]

Most of the ones I’ve worked on inject a variable DC current in to the 50Hz AC waveform. A bit crude but they work well. The more DC injected the courser the waveform becomes and the feed rate increases.View attachment 7771

 

[pmac10]

cheers Tony,think i'll go back tonight to get the make and model of the controller and do a bit of googling

 

[Knobhead]

A bit of a late addition but the ones I worked on were Locker Industries. The coil yolk could be up to ¾ ton in weight. Avoid them like the plague! The biggest feeders go under the name of “Brute Force”!

The rectifier was ½ wave. I’ll try and do a basic drawing, but it will be from memory!

 

[pmac10]

Tony, i know the the type of equipment you're referring to, i had a good tour of a lafarge cement works, like a quarry with a cement factory bolted on the side, 500 meter conveyors transporting boulders and vibrators which would almost knock you off you feet in the control room. This was a far more timid affair i was working at and i managed to grab the the electrical foreman coming off shift the next day, the controller was a frequency inverter and he showed me how to access engineers parameters like base frequency, resonant frequency and amplitude etc, more importantly, he showed me where the manual was kept.

 

[platty1005]

Hi PMAc the vibrating feeders i have encountered usually operate on 2 basic systems firstly an eccentric shaft driven by a motor. The motor AC or DC is then speed controlled to increase the speed of vibration. The second system is magnetic The feed plate is attached to a spring loaded membrane and the magnetic coil is located behind it. As the magnetic field energises it attracts the feed plate when it goes off the feed plate springs back away from the coil the stronger the magnetic field the more the feed plate moves. As in other posts Rectified DC, pulsed DC, thyristor controlled power modules all work to alter the magnetic field strength to adjust the feed rate.
You really need to dig out the system schematics and manuals to understand further but manufacturer and system serial numbers is a good start for google.
However installation/commissioning/maintenance manuals are the best info.

 

[pmac10]

thanks for the post platty, method two is what i was dealing with but i'm sure you can appreciate the ball ache of being called to troubleshoot unfamiliar technology on a system you don't know what working correctly actually looks like!(i didn't even know where those steps and ladders led to!), what you describe is how i imagined it to work in the first place so at least i'm thinking along the right lines, as mentioned earlier, i got the manual for the frequency inverter, so all sorted, but, i like to know more than just,'it works', pulsed DC, thyristors, smoothing etc all sit fine with me so if you have anything else you'd like to share, thanks in advance.

 

[netblindpaul]

pmac,
The only vibratory feeders I've worked on have been the vsd driven mechanical eccentric type.
Sorry!

 

[Knobhead]

pmac,
The only vibratory feeders I've worked on have been the vsd driven mechanical eccentric type.
Sorry!

Oh dear, they bring back bad memories! Ours were Locker Vymec.

First test run they ripped all the fixing bolts out of the wall and floor, it was two feeders cascaded so an awful lot of shaking and thrutching on a single frame. OK so bigger bolts, that didn’t work! They are animals.

The final solution (not that one) was to cross brace the whole lot between two 4-foot thick concrete walls. That fell to pieces with in a month. Locker reps were in despair this was the first big installation they’d done with the Vymec system. It was sorted in the end but Oh dear what a performance!

 

[platty1005]

Hi PMAC give us the name of the system and any other relevant info and I will give you more info if I can
The systems I worked on had a 400V thyristor/triac control to a single coil much like a simple dimmer switch for a light bulb. The bigger the voltage the bigger the vibration. As said before the tech manuals are the best place to start

 

[vaughant]

I'll find out the systems that we use (paper manufacture) as their very controllable and possibly more akin to the size of conveyor your using(around 3m/4m wide).
I've only been here 6 months and haven't had much to do with them so please excuse my lack of knowledge.

 

[pmac10]

cheers guys, Platty, its a Wright CD30 frequency inverter, with selection for single and double magnets, the conveyor itself has Wright plates on it so i guess they're responsible for the whole system, the manual i looked at was more of a users guide and googling just seems to bring up companies who fix or sell these drives.
and thanks also vaughant.