Hi There,

 

Can anyone explain AC Bleed to me?

 

Is it something I need to test for in a maintenance and if so how?

 

Also what parameters are acceptable and how do I ensure I am within these parameters

 

Any help on this matter would be greatly appreciated.

 

 

Many thanks 

 

Matt

AC bleed (inductance ?) in what regards cctv or intruder, if your looking fo inductance in alarm wiring, you need to measure between +12v and mains earth on a 20v ac setting, anything above 1vac is a potential for trouble

Brilliant, thank you, I am sure I was told about this some years ago as an engineer as I knew how to measure it but didn't know the parameters. Now I am starting out on my own I am trying to pick up as many things as I can.

 

Again thanks for the reply 

 

Matt

I would measure it as a standard on maintenance visits. High induced ac, usually caused by low voltage ( alarm) cables run parallel with mains 240v could cause random false alarms. ACT suggest fitting a 1313 filter on every panel/ psu inducing 1vac or more. If money were no object I would fit one on every end station, but I generally fit one if the induced is 12v or more and they have had a history of random ( multiple ccts) false alarms. Usually fitting one at the end station brings down the induced at the psu's anyway.

I have had panels though that have been in for years, no false alarms whatsoever, and 50/ 60vac induced, go figure

 

Mark

Act (who make filters) recommend fitting a filter with each system. Can't think why?

ive got a **** load of systems at well over 1v, with no issues, id only fit a filter if i had issues, most panels will sit there happy.

as above...

Took out an old Menvier the other day and found comment in log from 1998 or something

about 'mains float'. They had noted they'd wired panel 0V to earth to correct? (which was still

there).

 

TS700 I think, very odd panel in that the transformer itself was actually on the PCB rather than

in the chassis.

Edited December 4, 201312 yr by datadiffusion

ah the old grey panels with the big yellow sticker on the board lol, i havent seen that done before, but i have seen all spare cores of cct wiring taken down to mains stud in panel to make a drain for inductance

Must have been advanced for its time I suppose, tons of 'till roll' in the panel, guessing a printer

had been used at each service.