Battery Charger - 3 Ph Rectifier High voltage output

1. No load.

2. Check input voltage.

3. Sense wire not connected?

4. Mrs. Peacock in the Conservatory with a Wrench

4. I don't know the reference. Please enlighten me.

Google it if you don't have the clue

Colonel Mustard has been acting a little strange of late. Anyone seen the candle stick?

Generally, high voltage issues will be related to capacitors, but it might not be the caps INSIDE of your charger, it might be that they are interacting with capacitors elsewhere in your system due to resonance.

The DC bus on a rectifier fed by 380V will be around 535VDC, so for the output to be only 120VDC, there is a voltage regulator, most likely using PWM. But if the DC bus voltage climbs to above the tolerance of the charger, the regulator may not be able to change the output enough, or fast enough, to avoid tripping to protect your batteries.

Thanks Jraef!

The charger worked only on one phase sequence out of the 6 possible combinations. What could be the reason?

The voltage output from a charger can vary. So how many cells the charger designed to charge?

A 60 cell lead acid battery discharged the output voltage would be about 120 volts to start. Finish voltage would approach 150 volts.

Many come here with problems and give very little information to work with.

Scarlet with the candlestick

Get out the industrial hi voltage CRO. The SCRs could be firing early. They should be firing well down the tail end of the input sine curve, just before zero cross-over (about 20% of the peak amplitude of the sine wave). Is there cross-talk between SCR gate control circuits? Are the SCR gates too sensitive, so the gates pick up stray voltages easily? Substitute SCRs with less sensitive gates. SCR control is such a noisy process, there is garbage voltage all over the place. Try ferrite toroids or shielding on wires in the control circuits, especially if the gate control board is separate from the main board. A worn/noisy control pot.

I like your train of thought, if this charger has been in use for a while why the sudden change? has this been increasing for a while unnoticed or is this a new install? If it has been in service for a while something failed, wouldn't be at all surprised to find the filter caps have degraded and the feedback loop is responding to the AC ripple on the output. Anyone flip a switch or change a pot that hasn't been touched in a while?

It would help to know some history on this unit.

If your battery bank relates to a Solar PV system then there may be a better way to deal with the charging circuit. I cant understand the 3 phase charger being used though. how about some better explanation of the system involved.