Hi,
I have a power with dual winding primary of 115V
In series connection this will give me 230V primary.
Question is : is it OK/safe to insert 6v light bulb in between the windings (1st winding neutral -> hot -> bulb -> 2nd winding neutral -> hot) ?
The trans is around 35VA so the current in primary should be around 0.15amp max? I can use higher rating bulb to anticipate some turn-on surge.
The bulb meant to drop the voltage a little in secondary and can also functions as indicator light
Thanks in advance
I have a power with dual winding primary of 115V
In series connection this will give me 230V primary.
Question is : is it OK/safe to insert 6v light bulb in between the windings (1st winding neutral -> hot -> bulb -> 2nd winding neutral -> hot) ?
The trans is around 35VA so the current in primary should be around 0.15amp max? I can use higher rating bulb to anticipate some turn-on surge.
The bulb meant to drop the voltage a little in secondary and can also functions as indicator light
Thanks in advance
It's a very strange thing to do. Possible issue: it will eventually burn-out, killeing operation. Some later technician may "assume" a small lamp must be in a low-voltage link, and get an unexpected shock. Of course double unlikely since ALL incandescent lamps are going out of production, and eventually out of stock.
And 6V off 230V is hardly worth the effort? <3%?
A simple 150r 10W resistor does about the same, except a serious 10% reduction.
Indicator lamp today can and should be LED. While efficiency may be moot, life is so very much better.
And 6V off 230V is hardly worth the effort? <3%?
A simple 150r 10W resistor does about the same, except a serious 10% reduction.
Indicator lamp today can and should be LED. While efficiency may be moot, life is so very much better.
Electrically it would be OK.
But having a low voltage bulb sitting at 115 (or 230V with single fault) would be "misleading" with regards to safety.
I would not recommend this idea for that reason.
But having a low voltage bulb sitting at 115 (or 230V with single fault) would be "misleading" with regards to safety.
I would not recommend this idea for that reason.
The light bulb will have the opposite effect. The cold resistance of the bulb is very low and increases when it's hot. An NTC thermistor is the correct choice.
For your stated purpose the bulb can be at any point in the series chain.
However, I agree with others on the inappropriateness of the concept as a solution.
It´s a poor solution both as a power indicator (at idle circuit is ON yet bulb shines very weak, if at all so it´s misleading) and as a voltage reducer, since dropped voltage will vary *wildly* with power consumption, a mess.
Plus the possible danger because *nobody* will expect it to be wired direct to mains, being a low voltage bulb.
Bad, dangerous idea.
Plus the possible danger because *nobody* will expect it to be wired direct to mains, being a low voltage bulb.
Bad, dangerous idea.