diy projector from the Philippines

[TaskMaster]

Originally posted by Scubasteve2365
Is 240V 60Hz an electrical system somewhere?

I know some baseboard heating systems run off 240V. In the US typically electrical panels are supplied with at least two opposing phase hot 120V lines. To wire 240 you just wire a breaker across these two hot lines. I have a 240V outlet here in my basement for a welder (that is long gone).

[Scubasteve2365]

Originally posted by TaskMaster


I know some baseboard heating systems run off 240V. In the US typically electrical panels are supplied with at least two opposing phase hot 120V lines. To wire 240 you just wire a breaker across these two hot lines. I have a 240V outlet here in my basement for a welder (that is long gone).

Yeah, I know for high power situation we have things like that here in the states ..... there are 3phase systems in either Y or delta configurations that alot of manufcaturing facilites use to drive their equipement (belt motors and such)

but I was unaware of that being a standard, in every house plug your your hair dryer into the wall system ....

[TaskMaster]

Yep, this is the reason why electricians usually install the breakers in a balanced number between the left and right columns in a breaker box, e.g for six breakers it would be two colums of three instead of one column of six. This balances the load between the different phases wired to the box (typically one phase supplies each column).

[Goemon1966]

Originally posted by Scubasteve2365

BTW .... I graduate soon with My Electrical Engineering Degree from Purdue University, I didnt make any of the above up .... but rather payed a pretty penny for someone to teach it to me ...

Is 240V 60Hz an electrical system somewhere?? ..... I thought it was only 240V 50Hz ..... I live here in the states so I dont pay much attention to other systems ...... Even though I wouldnt try it, for the sake of the life of the ballast .... the ballast probably has some reactive components in it, and this will increase current. The current increase Very well may be safe and stable and the ballast could operate for years to come ..... but ...at the same time the current increase may be toooo much for the ballast, and it might cough out after a few days .... The only way this question could be truely answered properly was if someone looked at the internal components of the ballast.... My guess is that they use a High power Voltage to Current convertor cicruit then run that through a Current to Voltage converter circuit so that you have a perfectly stable 400 (UNITS Either W OR VA) of power coming out. If thats the case you could exceed the power/current threshold of the Op amps or whatever, but again no way of knowing for sure unless I got to see the Ballast's insides ....


-Scuba-

Well Scuba,

Whatever you paid for that sterling education, you clearly didn't pay enough.

You say an INCREDIBLE amount without actually answering the question.

In fact, you say just enough to indicate that you got the facts COMPLETELY wrong.

That aside, I am VERY impressed with your algebra...




Hertz: Thanks for your help. I am happy to risk a ballast collapsing within a matter of days.

[TaskMaster]

hertzblaster,

I just browsed through and must say - your pics of your image are incredible!

[hertzblaster]

Scubasteve2365,

Sorry if i sound offending in my reply but i don't meant it that way.

Thank you for reminding me how to get the power factor mathematically.. Its just that i thought we need to test it in a real world with a meter to get the realistic result. We will need given data in order to come up with our computation.

All i want to say to goemon run the ballast under correct operating condition to get the best result. Running the ballast undervoltage will give you bad result.
Its true that the lamp will draw more current from the ballast but the lamp brightness will suffer.

I have a variable power supply and i had an idea already how bright my lamp will be at different voltage and current supplied to the ballast and the lamp. A wattmeter could help us out better in determining power (watts) consumed by the lamp. ( 250 watts Hqi-tsd is rated to run at 100v at 3amp.)

BTW, I have 3 Hqi-bulbs and you will be surprised that each operate at different voltage using the same ballast. The one that operates at higher voltage is brighter than the others. The one that operates at higher current at lower voltage is dimmer. At least base on my subjective experiment..

I've been reading the tutorial from Advance transformer about how to get the best from HID ballast and i guess being an electrical engineer like us has an edge to easily grasp the knowledge and can easily share and explain it to the others the simplest way possible.

Regards,
Hert

[hertzblaster]

If for any reason there is a voltage drop, then the ballast should SINK more current through the bulb to maintain the proper wattage, however there is a point when TOO much current will be drawn. If there is a drop in voltage then if anything the ballast will run hotter due to the current increase ... however I think that It will run at approximatly the same temp because no matter what your still dissapating a fixed wattage of either 250W or 400W.

Here is what i thought it will be . Please correct me if i'm wrong.

The high current will cause the ballast to heat up, not the power it delivers to the lamp.

example using the same ballast
Ist condition : 100 volts x 2 amp = 200va

2nd condition ; 50 volts x 4 amp = 200va

Condition 2 will run hotter because of bigger power consumed by the ballast. Ballast temperature will be different under this 2 operating condition.

[Scubasteve2365]

Originally posted by hertzblaster


Here is what i thought it will be . Please correct me if i'm wrong.

The high current will cause the ballast to heat up, not the power it delivers to the lamp.

example using the same ballast
Ist condition : 100 volts x 2 amp = 200va

2nd condition ; 50 volts x 4 amp = 200va

Condition 2 will run hotter because of bigger power consumed by the ballast. Ballast temperature will be different under this 2 operating condition.

Yeah, I think the same thing ..... the higher current will theoretically yeild more heat transfer ... especially since voltage is just "current potential" anyway ..... but .... most of any heat that you can feel is often power ... especially coming from an electronic device that has heat sinks and what not ..... I honestly believe that both temps above will be very very close in temperature .... If I had to pick one that would run hotter it would be the 2nd condition No doubt .... but since they are both dissipating the same amount of power then they SHOULd be very close in temperature.

That is assuming that in both conditions the circutis are stable... If the 2nd condition is TOO much current for the circuit, as to where all the internal devices are running hot, and reaching their threshold ... then the 2nd condition will run alot hotter ... but not for long, before something releases the magic smoke .... and it no longer works ....

I also think alot of this will matter depending on if your using an electronic ballast, or an old coil ballast. Im using a coil ballast, and the thing spits out a consistant 275V-300V with an open load (No Bulb) ... I havnt really measured with the bulb in ... but im certain that different bulbs will draw different brightness (even if they are supposed to be the same)

[Scubasteve2365]

Originally posted by Goemon1966



Well Scuba,

Whatever you paid for that sterling education, you clearly didn't pay enough.

You say an INCREDIBLE amount without actually answering the question.

In fact, you say just enough to indicate that you got the facts COMPLETELY wrong.

That aside, I am VERY impressed with your algebra...




Hertz: Thanks for your help. I am happy to risk a ballast collapsing within a matter of days.

i did answer the question ... sorry if I didnt put it into a simple matter of sure plug it in, or dont plug it in .... Sometimes things arent that simple ......

but Im curious to know what FACTS, I have wrong .... better yet completly wrong?? Please Educate me where my Professors have failed to do so ..... LOL ...

[hertzblaster]

then the 2nd condition will run alot hotter ... but not for long, before something releases the magic smoke .... and it no longer works ....

I had read ( can't rember the site) that newer UL certified electromagnetic ballast is thermally protected. This may somewhat give us a piece of mind when we think about the danger of overheating ballast.