Experienced Electrician! Here to Answer Any and All Growroom Electrical Questions
- Thread starter bricktown73
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Danielsgb
Well-Known Member
IAm5toned could say, or that answer may be in his thread I showed. I'm pretty sure he told me that good & simple reason once but I forgot. I do know they need to cool down for 10-15 min. before they re-start.
duchieman
Well-Known Member
Sorry to continuous post but I just thought of something. It was mentioned to cool a magnetic ballast for 15 mins between bulb switches. If the ballast is going to continue powering one of the bulbs, why does it have to shut down at all, therefore requiring cooling before restarts. Which made me think of this. Lately we've been having quick outages and surges that knock my light out, and when it tries to fire back up, it won't until after a cooling period. I always thought it was the bulb that needed cooling but now I'm wondering if it's the ballast? But then again, I remember one time the bulb wouldn't refire so I grabbed a new one right away and it worked immediately. Later on, after some days, I switched them back and all good. So there is a question in there somewhere.
IAm5toned
Well-Known Member
to understand why a ballast needs a cool down period, first you need to understand how an HID lamp works, on startup.
hid lamps have a bimetallic element on the filament that switches the current between the preheat filament and the arcing tube
the load characteristics of a preheat filament, and an arc tube, are completely different.. a preheat filament is a resistive load, and arc tube is an inductive load
a resistive circuit, at room temperature, when you apply power to it, has a resistance of 0 ohms, untill the filament begins to heat up and act as a resistor, which in turn heats up the arc tube, and when it gets hot enough, the bimetallic element switches the current to the arc tube... but the key here, is that 0 hms on the preheat circuit... because electricity, flowing through 0 ohms of resitance, generates whats known as inrush current. Flipping the switch on a circuit that has 0 ohms is equivalent to blowing a dam up.. the lake empties quick! but it only lasts for, quite literally, nanoseconds at best.. because the preheat element heats up the instant you start passing power through it, and when it heats up, its resistance rises proportionate to the amount of heat... now that you know what is happening during lamp startup, so here's why a ballast needs a cool down period between lamp starts:
a hot ballast is too hot for the inrush current on a cold lamp, over time, the inrush will destroy the insulation between the ballast windings on the main transformer... it mkes the insulation brittle over time... the ballast isnt engineered to be restriked (restrike= hot start) at all, its engineered to run for a min of 8 hours with a 30 min cooldown.. and thats kind of an industry standard between major manufactuers.
they (lighting manufacturers) say 30 mins, for warranty reasons... because they know if your constantly restriking your ballasts... they wont last... and they wont have to honor a warranty
hid lamps have a bimetallic element on the filament that switches the current between the preheat filament and the arcing tube
the load characteristics of a preheat filament, and an arc tube, are completely different.. a preheat filament is a resistive load, and arc tube is an inductive load
a resistive circuit, at room temperature, when you apply power to it, has a resistance of 0 ohms, untill the filament begins to heat up and act as a resistor, which in turn heats up the arc tube, and when it gets hot enough, the bimetallic element switches the current to the arc tube... but the key here, is that 0 hms on the preheat circuit... because electricity, flowing through 0 ohms of resitance, generates whats known as inrush current. Flipping the switch on a circuit that has 0 ohms is equivalent to blowing a dam up.. the lake empties quick! but it only lasts for, quite literally, nanoseconds at best.. because the preheat element heats up the instant you start passing power through it, and when it heats up, its resistance rises proportionate to the amount of heat... now that you know what is happening during lamp startup, so here's why a ballast needs a cool down period between lamp starts:
a hot ballast is too hot for the inrush current on a cold lamp, over time, the inrush will destroy the insulation between the ballast windings on the main transformer... it mkes the insulation brittle over time... the ballast isnt engineered to be restriked (restrike= hot start) at all, its engineered to run for a min of 8 hours with a 30 min cooldown.. and thats kind of an industry standard between major manufactuers.
they (lighting manufacturers) say 30 mins, for warranty reasons... because they know if your constantly restriking your ballasts... they wont last... and they wont have to honor a warranty
duchieman
Well-Known Member
That was a great explanation, thank you for that. So restriking a ballast is harmful if restruck on a resistive circuit, cold filament, but what about when the power surges and knocks out the ballast and bulb for a second and the resistive circuit is still hot and resistive, why will the lamp not light then? I ask because I wonder what would happen if I'm not home when it happens, to unplug the lamp and let it cool. Also, if it did happen while I was away, would I even know it? By that I mean, will the lamp eventually ignite on it's own again? I've never let it go that far when it happens.
I now have another question about an experience I had with a faulty dual arc bulb, but I'll save that for next
I now have another question about an experience I had with a faulty dual arc bulb, but I'll save that for next
IAm5toned
Well-Known Member
because the bimettallic element that actually does the switching, needs to cool down enough to close the circuit to the preheater... it doesnt retrike the lamp, because its still too hot to close.. but not hot enough to restablish the arc inside the arc tube... establishing the arc inside an arctube, is actually a very fine science... if the element is too hot, it wont work, if its too cold, it wont work.. the conditions have to be just right.... the gaseous element is actually plasma, and plasma has strange properties... to sum it up, for it to work right, an arc must be established in the gaseous element while its not hot enough to become plasma, but not cool enough to have too low of a resistance, and as the gas heats up, it begins to flouresce, and tada, you have light. while the arc tube is hot... the resistance is too high for the arc to even start.. so it has to cool down
im sure youve seen a lamp flicker while starting up.... that is the preheat circuit witching between the arc tube and the preheater... you can even hear the inrush current growling if you pay close enough attn...
im sure youve seen a lamp flicker while starting up.... that is the preheat circuit witching between the arc tube and the preheater... you can even hear the inrush current growling if you pay close enough attn...
duchieman
Well-Known Member
Great explanation again. So does that mean that if I wasn't around to unplug the ballast after such surges, that the bulb would not ignite again, even though the ballast is still running? If so, what are the negative affects of this?
The story of my dual arc is that one morning it was trying to fire up and the ballast was klunking and arcing inside, with that nice electrical burn smell. I immediately looked at the bulb to see whats happening, and if I recall now, the MH part of the bulb was having trouble igniting, then the klunk (like it was resetting), and the bulb would try again. I immediately unplugged the ballast, changed to a regular HPS and no problems since. Guy at the retailer said faulty bulbs due to different life spans between HPS and MH. Don't know what to think of that explanation.
The story of my dual arc is that one morning it was trying to fire up and the ballast was klunking and arcing inside, with that nice electrical burn smell. I immediately looked at the bulb to see whats happening, and if I recall now, the MH part of the bulb was having trouble igniting, then the klunk (like it was resetting), and the bulb would try again. I immediately unplugged the ballast, changed to a regular HPS and no problems since. Guy at the retailer said faulty bulbs due to different life spans between HPS and MH. Don't know what to think of that explanation.
luckandleather
Active Member
You are 100% correct, Thank goodness I'm off the grid, so to speak. my landlord pays it all and there are other power consumers on same meters. No smart meters here. If one show up I'm going totally off(u can take that any way you want) it's bad enough all my internet use is being mined.
IAm5toned
Well-Known Member
thanks.
sometimes i feel like the boy who cried wolf... til i read the news and hear of yet another bust due to tapping....
luckandleather
Active Member
They have a name for that, why people don't listen and don't think it can happen to them, it's called the "normalcy factor". It's not that they are stupid, they just think because they don't see it happening then it means it's not happening.
benny blanco
Active Member
Can I run 2 1000whps on a 30amp fuse? (My pannel still uses fuses lol)
luckandleather
Active Member
Electrician question, I wired up a bathroom fixture, a 4 bulb vanity light, to suspend from ceiling. I used and old extension cord for the wire, but it lacks the ground pole wire, a black wire and a white wire only. So I attached the ground wire( a bare copper wire) that is on the bathroom fixture between the eye bolt and nut/washer on the backside(using 2 eye bolts for hanging the light)of the fixture.
Is this a good ground? The light works, all the wires are properly connected with wire nuts and taped over with electricians tape.
The extension cord is a common orange cord, it just didn't have a ground pole end.
My other concern is how high humidity with affect the connection in the sockets, both the vanity sockets and the y connector sockets, even the cfl bulbs. Should I go back and apply a conductive lubricant ?
Is this a good ground? The light works, all the wires are properly connected with wire nuts and taped over with electricians tape.
The extension cord is a common orange cord, it just didn't have a ground pole end.
My other concern is how high humidity with affect the connection in the sockets, both the vanity sockets and the y connector sockets, even the cfl bulbs. Should I go back and apply a conductive lubricant ?
IAm5toned
Well-Known Member
you will be fine..... they take high humidity into concern when designing bathroom fixtures
and code says a light fixture with a cord length shorter than 8 foot is not required to be grounded...........
tho for safety's sake, it always helps to have a path for fault current.
and code says a light fixture with a cord length shorter than 8 foot is not required to be grounded...........
tho for safety's sake, it always helps to have a path for fault current.
smokey green
Active Member
From a fellow electricician to another, great thing what your doing here man, the thought of a lot of do it yourselfers on a stoner forum is somewhat scarey...lol....+rep
luckandleather
Active Member
you will be fine..... they take high humidity into concern when designing bathroom fixtures
and code says a light fixture with a cord length shorter than 8 foot is not required to be grounded...........
tho for safety's sake, it always helps to have a path for fault current.
the cord is aprox 9'
smokey green
Active Member
sure can , your looking at using 18 amps with 2 1000 watters...just keep in mind the other loads (if any) that are on this 30 amp circuit. you should probably have a 20 amp fuse in place of the 30amp ....If nothing else is going to be on this circuit, I would suggest using a 20 amp fuse instead...that way the fuse will blow quicker if there is a problem.
(just thought Id give you a quick hand here brick, looks like you got your hands full...lol... ps. im not new here (been on riu since 08, just decided to make a new account)
(just thought Id give you a quick hand here brick, looks like you got your hands full...lol... ps. im not new here (been on riu since 08, just decided to make a new account)
