Motor Braking

[Steve_D]

Gents, we have some vibrator beds (415v .8kW 2.4amp DOL) and due to some excessive vibrating on shut down we require a method of stopping them ASAP. Can someone suggest a DC injection braking unit I could use (VSD's will be too expensive (we need 16)) or some other option.
Regards Steve D

 

[CroCop]

What do you have controlling the contactors?

Can you add a second contactor with a brake resistor driven for a small duration by a PLC or something similiar?

 

[rsdoran]

I am not sure that drives would not be an option, at that rating you are talking about a 2HP drive (sorry but use to HP used in referenced to motors etc). The cost for a drive in that range, especially if 16 were bought at one time, could be $250 US or less maybe. I am not sure a DC braking system would be any cheaper. I think you would still have to change the contactor too to use a DC injection system.

The other option could be electro-mechanical braking but that would require changing motors probably so the cost may be just as high.

To give an idea this page shows prices for DC injection brake systems.
http://www.inverter.co.uk/electricmotorcontrols/dcinjectionbrakes/dcinjectionbrakingunits.htm

This is the AD page for some inverter pricing: http://web3.automationdirect.com/adc/Shopping/Catalog/AC_Drives_-z-_Motors/GS2_(115_-z-_230_-z-_460_VAC_V-z-Hz_Control)

It is possible you can do better from one of your regular suppliers.

 

[DickDV]

Check with Benshaw INC. in Glenshaw PA. They make a DC injection module that is designed to work beside a mag starter. Every time the starter opens, the module shoots DC into the motor for an adjustable period of time at an adjustable current level (thereby controlling the braking intensity).

Inexpensive too! No, I don't sell them! I did about 10 years ago but, no more.

 

[504bloke]

I have used many many dold units and can recommend them 100%

We always fit thermistors to the motors being braked and link in a thermistor module

Check out

http://www.dold.com/englisch/Schaltgeraete/Leistungselektronik/body_leistungselektronik.htmlhttp://www.dold.com/englisch/Schaltgeraete/schaltgeraete.html

Your distributor

Australia

Electrical Control Automation Pty. Ltd.
4 Elida Place
Wheelers Hill, Victoria 3150

Tel.: (+61) 3 - 95 74 76 22
Fax: (+61) 3 - 95 74 76 33
eMail: [email protected]

 

[Steve_D]

Thank you guys, I will check out your solutions

 

[andybutcher]

Thats all too complicated. just install a second contactor and timer and plug stop the vibrator. Plug stopping reverses the phases to the motor on stop for a minimal time. The timer controls the amount of time the stopping contactor is energised for. You will have to experiment with the time, but it should be set so the motor slows quickly not allowing it to reverse. I have use this system on vibrating feeders that were 22kW.

Hope this helps.