Inverter help

[Paul1985]

Hi iv been asked to fit a 3 phase inverter to a motor with a 230v brake which is using the star side of the motor for the neutral. Now iv fitted inverters before with a brake i know they make them chatter so you put a contacter in to switch the brake separately. My problem is the neutral there isn't one so i cant separate it from the motor i can take a separate live but not a neutral. Are my only options change the coil voltage or put a neutral in.

 

[Bobster]

Draw a quick sketch of the circuit your trying to produce.

 

[Paul1985]

Will do if i can figure how to put pics on here lol. Only other way i can think of is put a transformer in from 415 to 230.

 

[Bobster]

Easiest way is to upload the photo to a hosting site such as photobucket. I suspect you might not have permission to post photos direct to the site yet.

 

[Charlie_]

You need to run a separate supply to the brake through a contactor and controlled via one of the inverter relays.

 

[Paul1985]

I get all that bit as iv done it before with 415v brake and brake rectifier but this is old and uses 230v which is tapped from the star side of the motor to act as the neutral. Like i said probably with running it separately is there is no neutral which is why said is the only way to run a neutral change the coil if it can be re wound to 415 or just put a transformer which will allow a separate Feed. Or is there any other options i might have missed

 

[Charlie_]

Am I right in saying that you only have a 3 phase supply with no neutral to the inverter?
If so, then yes, use a Tx on 2 of the supply lines to give you 240v or 230 depending on age of the motor..

The inverter can then control a braking contactor using one of
its aux relays.. Don't use the inverter relay to control the brake directly.

 

[Paul1985]

Yer theres no neutral at all. Iv not got the inverter yet just looking at the job and seeing what options i have got but think iv answered my own question. cheers