Battery Charger Ripple content

If the ripple is a new thing, then I'd suspect that you've lost one of the filter capacitors in the charger. If your redundant supply (or battery) isn't kicking in at the right time, then you should check the voltage from each supply, upstream from the diode. 15 years is getting old, maybe it's time for repair or replacement.

If you plan to replace the old chargers, get at least 12-pulse (or 18-pulse is better) rectifier. This will be expensive but help to reduce the ripple factor in the DC system and harmonic current in the AC input side.

- MS

Please replace the filter capacitors. They have lost "ability to filter". As a ISO 9001-2000 (tuv) certified manufacturer of battery charger for power plants and substations, we regularly face this issue and suggest our customers to replace it once in 6-7 years.

Thanks and regards

Ashok Toshniwal, Bangalore, India.

Dear Friend,

Failure of plant machinary PCBs is due to repple content in the DC. The repple content can be avoided in two ways.

1. With the help of filter units (if they are in the cubicle, it should be working perfectly and can be asscertained through oscillators)

2. By replacing the SCR(Semi conducting rectifiers) which are not performing in the circuit.

Good luck

CVS Murthy

Manager Projects

Electric Power Division

GMMCO Limited.

Mobile: 09866550981

You will find some big large electrolytic capacitors at the out put. These electrolytic capacitors capacity goes down due to ageing effect. Add some more capacitors or just replace them and your problem will be solved. The other Chance is "out put choke failure". This is very rare but chances are there. Hence check choke rating; is it same as marked or not. I am assuming that the CV charger is in-perfect working condition. If any one SCR fails also the out put ripple will increase. In electronics the only component that is effected by ageing is Electrolytic capacitor.

Regards.

Battery itself is considered to be an infinty [∞] Capacitor and inspite there are a lot of batteries in back-up I wonder if either the measurements are misleading or the batteies are flat.

Check the batteries on HRD [Hi-Rate Discharge] tester for actual condition of batteries

Thank you all for the replies with your comments. We are in the process or replacing the filter capacitors and will be replacing the charger by the end of next year. The possibility of procuring a 12 pulse charger is being discussed for cost - benefit. The 12 pulse seems to be more prevalently used for UPS & VFDs for reducing harmonics.