RE: [CAD_CAM_EDM_DRO] AC to DC quesiotn, old worklight

I wouldn't worry about whether the supply to the bulb(lamp is actually the
technically correct term) is DC or AC. It is true that the inductance of a
filament may cause a slightly lower current to flow in an AC situation, but
I wouldn't worry about it.

From Chicago Miniatures Website FAWs:

"An incandescent lamp will operate on either AC or DC, but when operated on
DC a 50% life reduction will occur due to a phenomenon known as DC
notching."

So go ahead and use the AC.

Andy Wander
Vice President, Engineering

Verrex Corporation
(908) 232-7000
(908) 232-9065
(610) 847-5947 Home Office (Wednesdays)
(610) 389-4819 Cell

-----Original Message-----
From: volitan712003 [mailto:volitan@...]
Sent: Thursday, September 30, 2004 2:16 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] AC to DC quesiotn, old worklight


Hello,

I'm helping a friend with a real old Mori Seiki (sic?) lathe. Of all
the things to obsess over, he wants the worklight to be functional
from the original switch on the control! All that's left from the
original light is a housing and a "dish" that hold the bulb.

There's a sign near the light that says to use a 24v, H3 Halogen bulb.
We managed to find these on-line. Trouble is when I measure the
voltage going into the switch, it's around 24 volts alright, but it
seems to be AC?! I have no idea of the amperage.

I'm assuming the bulbs are DC, although I haven't tried it yet. I'm
also assuming there was some type of current converter originally in
the housing itself (there's an awful lot of room in there for just a
bulb).

If I'm right on this, should we be able to use a bridge rectifier and
a variable resistor, after the switch, to convert the voltage and
bring it back down to 24v? Would a cap be necessary? And Am I just
barking up the wrong tree altogether?

I suggested a totally new worklight, they're on ebay cheap enough. But
he wants to try it this way first... He really likes this old clunker,
and wants to try and keep it original.


Thanks
David




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