we have hundreds of magnetic type feeders in aggregate.........sand and gravel. and almost nil electro-mechanical in this industry.

conversely, you will find hundreds of electro mechanical type feeders in the coal industry .....NO spark for source for igniting coal dust. ■

Originally Posted by wkc2009

Dear All,

I am a newbie here.

I would like to know what would be the difference between using electromagnetic feeder against electromechanical feeder(using unbalance motors)?

Does electromagnetic feeder have lesser maintenance problem compare to electromechanical feeder?

I am thinking of designing a feeding system for sugar but unsure which would be better suited. The capacity is approx. 200TPH.

Appreciate some advise and thank you.

Dear wkc2009,

it depends what you need.

If you need exact regulation of capacity you need electromagnetic drive system.

With electromagnetic drive system you are also able to regulate capacity from nearly 0% to 100%. Electromagnetic drive system also stop immediately when you have reached amount of material you need.

Unbalanced motor driven feeders are most time little cheaper when you need no regulation of capacity. When you want to have regulation of capacity you need frequency converter. With this you are able to regulate capacity from appr. 40% to 100%.

If you go lower it could be possible to have troubles with synchronisation of motors. When you stop feeder it need few seconds until feeder stand still.

I hope information was helpful for you

Chris ■

We manufacturer feeders, low rate like you are stating, utilizing both eletromechanical and electromagnetic. The emags are very limited in turndown range and are dramatically affected by headload changes - thereby negatively affecting your feed rate accuracy. We use them primarily when we need to spread product over an area, very accurately.

Emechanical units allow for over 100:1 turndown range. No moving parts per se. Not affected by headload and come with a 3-year warranty.

We've done sugar feeders as you stated. Check out our website. Lots of detailed info here to help you.

Scott Dahlgren

www.3Sigma.biz

scottd@3Sigma.biz

704-846-1617 ■

I just read Chris' post. When dealing with feeding dry bulk solids, fine in nature, at rate you stated, the 0-100% will not hold nor the 40-100%. Accuracy is not dependent upon this drive in this application.

Also all VFD's supplied come with a braking system so that the electromechical drives stop instantly. That, in fact, is a huge selling factor for us in selling our feeders in batching applications... for 90% of apps we use electromech.

FYI.

Scott Dahlgren

3Sigma ■

Our two-mass electro-mechanically driven feeders can have a turn down rate from 100 to 0% +/- without slowing the motor speed when utilizing our Variable Force (VF) wheels. Two-mass units typically utilize 1/3 the energy of direct drive (brute force) units.

Should you be interested, here are some links for more information about the technology.

Para-Mount II® Vibratory Feeders

Two-Mass Technology Explanation

Variable Force (VF) wheels

Thank you,

Thomas Musschoot

General Kinematics Corporation

www.generalkinematics.com ■