Pig tails working on DC

[QUAZ HOLT]

The coil lights say that they run on 110v AC so I decided to test them on DC. Having an old square wave inverter that keeps burning out the fets I opened it up to fix it for the last time. Bypass the H switch and mark the output as 120 dc. "The voltage out is actually 167 volts dc" I wanted to do this because the coil light has a bridge diode and high voltage capacitor. It just turns the AC voltage back to DC anyway. Plugged it in and it works. The light has been working in the bathroom for a year now.

The lamp is just temporary a year ago.

Voltage on the cap. is 167 volts dc so make sure it is discharged. cut the traces from the high voltage capacitor and wire it directly to the inverter output. You can remove the old H switch by cutting traces and removing wires. The wall switch is now replaced with a low voltage switch connected in parallel with the inverter power on switch. This way the circuit has a soft start.

Electrical experience is required to do this. Bill.

[whatsnext]

How bright is it when run at 167VDC instead of 120VAC? And, is there a point to doing this other than proving that it can be done?

John..

[QUAZ HOLT]

How bright is it when run at 167VDC instead of 120VAC?


John. Bill here. When you convert 120 volts AC into DC through a bridge diode the voltage obtained is 167 volts DC. (118VAC x 1.414 = 166.9). Most AC equipment running at 110 to 120 vac that have circuits with diodes actually run at ~167 volts dc. The coil light runs at 167 volts DC.
12 volts DC to 167 volt dc to 120 volts ac to 167 volt dc to 300 volts ac then light. This is how a 12v sine weighted inverter works to run a coil light.


To make a long story short same brightness less power. Bill.

[Nando]

Well, some electronic ballasts for fluorescent lamps do require AC, because internally they have a voltage doubler for 320 volts operating from the GRID frequency.

Most of the cheap fluorescent electronic ballasts have 2 high voltage transistors ( the patent elapsed a few years ago) and have a full bridge rectifier so they will take from about 95 to about 180 volts DC.

A few lamps now, do operate well with DC or AC because they have internally a PFC circuit to bring the internal voltage to 380-400 volts, some may have dimming capabilities as well.

Nando