julianf
Member
- Messages
- 8,713
- Location
- devon, uk
I have a uv exposure unit.
The uv is provided by a single metal halide bulb, of unknown spec.
To turn the bulb on, the whole unit is switched on, and then there is a "momentary" push button switch to manually light the bulb.
There is a "high / low" switch for the bulb, which, I think, is supposed to lower power consumption / increase bulb life in a commercial environment, where, I assume, the unit is started at the beginning of the day, and then used periodically throughout the day (when it's switched to "high" and then switched back to "low") - however I'm not certain of this.
The control timer for the unit has a photosensitive resistor which is supposed to increase exposure units as the bulb ages.
The exposure is controlled by mechanically operated shutters as the bulb stays on all the time.
I mention all this for background. My question relates to the bulb starting -
Recently the bulb has been taking longer to start. An (approx) second, or fraction of a second on the momentary "start" button has turned into a few seconds.
Id like to know why?
Is this ambient temperature (it's in an unheated building, but it's not especially cold here in Devon currently) or is it bulb ware, or, I assume, there's some big capacitor somewhere that has to charge - is it going to be the cap?
The bulbs are insane money to buy from the manufacturer of the equipment. Like 3 or 400 plus the vat. A cap isn't going to be so much, I guess.
My problem is that there is change in the unit, and that generates fear. If I have a rush job and it fails to turn on, I'm stuffed.
So I'm trying to guess (or rather ask here) about what may be failing, so as I can prepare for failure.
Thank you.
(Really bad photo below)
The uv is provided by a single metal halide bulb, of unknown spec.
To turn the bulb on, the whole unit is switched on, and then there is a "momentary" push button switch to manually light the bulb.
There is a "high / low" switch for the bulb, which, I think, is supposed to lower power consumption / increase bulb life in a commercial environment, where, I assume, the unit is started at the beginning of the day, and then used periodically throughout the day (when it's switched to "high" and then switched back to "low") - however I'm not certain of this.
The control timer for the unit has a photosensitive resistor which is supposed to increase exposure units as the bulb ages.
The exposure is controlled by mechanically operated shutters as the bulb stays on all the time.
I mention all this for background. My question relates to the bulb starting -
Recently the bulb has been taking longer to start. An (approx) second, or fraction of a second on the momentary "start" button has turned into a few seconds.
Id like to know why?
Is this ambient temperature (it's in an unheated building, but it's not especially cold here in Devon currently) or is it bulb ware, or, I assume, there's some big capacitor somewhere that has to charge - is it going to be the cap?
The bulbs are insane money to buy from the manufacturer of the equipment. Like 3 or 400 plus the vat. A cap isn't going to be so much, I guess.
My problem is that there is change in the unit, and that generates fear. If I have a rush job and it fails to turn on, I'm stuffed.
So I'm trying to guess (or rather ask here) about what may be failing, so as I can prepare for failure.
Thank you.
(Really bad photo below)
probs one of these or simlar about 15 diffrent types 
specialist lamp then. not much chance of grafting anything else in cheaper
