Flouresent lighting questions for the wizards

wrote:


Why not? You are slightly underpowering them - but if they work you most certainly will not be harming them.

What do you expect this to accomplish?

How about running two circuits - one on ballast #1, and one on ballast #2 - with separate switches. You can light the whole fixture, or either half, depending how much light you need. You could also add a switch to drop out one half of the shop if you are only working in the other half, so you could have the "active" end of the shop at full or half, with the "inactive" end either on or off. Just 4 standard switches.
Many other combinations available, Just remember, the pull-chain switches NEED to be rated for 240 volts minimum.
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On 9/9/2012 7:44 PM, snipped-for-privacy@snyder.on.ca wrote: >> 2. Is it better to use a transformer and isolate them from the "mains >> power"? > > What do you expect this to accomplish?
My parents house had all fluorescent fixtures in the basement except for a single incandescent bulb all on one circuit, that bulb was frequently blown by the mag ballast's spiking when turned off, so it can be good to isolate fluorescent fixtures if electronics are on the same circuit. MikeB
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wrote:

Except the isolation transformer will just pass the spike right through. A surge protector might catch it.
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wrote:

Indeed. While my shop has VFDs, and other Stuff..I like to keep it as "clean" as possible. Ive had to hunt down too many issues in the machine shops I service to jumble it all up
Gunner
-- "Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry
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On Sun, 09 Sep 2012 19:44:03 -0400, snipped-for-privacy@snyder.on.ca wrote:

Arnt they so rated? I assumed (ass you and me..yah I know) that they would be rated for at least that much. No true?
And thanks!!
Gunner
-- "Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry
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wrote:

Some are only rated for 125 volts AC

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    [ ... ]

    [ ... ]

    The cheapest way would be to get a step-*down* transformer which goes from 240V to around 40V and hook it up with the primary across the line, and the secondary in series with one side of the line phased so it adds to the voltage (if it drops the voltage, just interchange the two secondary wires).
    Probably easier to find ones which put out 28 VAC, which will get you up to 268 VAC -- close enough for most purposes -- especially with your slightly higher line which I think that I already trimmed out.

    You really want the number of amps -- which can be higher than the Watts would indicate. Do you have a clamp-on ammeter? If so, that should tell you what you need. (The power factor in the ballast is something which I could not predict.) But because the boost transformer I described does not have to provide the current at the full voltage, it can be smaller. A 28 VAC transformer at 1A is a lot smaller than a 277 VAC transformer at 1A (28 VA vs 277 VA -- so nearly a factor of ten in the weight). And a 1A transformer can supply 268 VA boosting a 240 VAC line.

    What would probably draw the least power would be LED lamps, but the price on those is far from low enough yet -- aside from you not being in a position to buy new which is all there is out there in the LED family. So it would cost you less to *run*, but way too much to *acquire*.

    Hmm ... how many relays can you find in the junk pile? Look for ones with AC coils for 24 VAC, 120 VAC or 240 VAC -- whatever you have most of. Set them up so you switch power to the relay coils from a convenient location -- so turning off the power to one set of relays will turn off half the lamps in each fixture. Turning off the power to the other set will shut down the other half. Maybe set it up so a rotary switch powers the coils. If you have a four-deck switch with five rotary positions -- you can have it so fully CCW has all the lamps off, one step up turns on 1/4 the lamps, the next step 1/2, the next step 3/4 and the final step all of them.
    If you have a bunch of solid state relays, you could use them instead -- they use a lot less power (anything from 3VDC up to 32 VDC IIRC) and almost no current.
    If you want to be able to do it from multiple locations, replace the rotary switch with a stepping switch. Wire it like the rotary switch, but you have the ability to push a button to step it through the positions from a number of locations around the shop. There was one style of stepping switch by Automatic Electric which had two coils. One would step it up from a rest position to any one of ten active positions, and some of them had as many as four decks and wipers. So -- you push one button to increase the light, and another to turn them *all* off at once.
    Of course, you want a master disconnect to make it safe to work on the circuits -- especially since it is possible for the SSR to fry in the *on* state -- especially if there is nearby lighting.
    If you already have stepping switches like these (eBay # 120645014544), you can wire them up so if you hold a button down, they will keep stepping up so you hold the button down until it is bright enough, or until it goes dark again.
BTW    For anyone looking for stepper switches on eBay currently     *Beware*! A lot of what are being sold as stepper switches are     in reality only the bank of contacts, without the rotary wipers,     or in some cases with the wipers, but without the     electro-magnets which perform the stepping.
    I was trying to find examples of the 10 position quick reset     ones to show you what to look for in the "pile of junk" -- but     nobody has them up for sale at the moment.
    If you want more details, you have my e-mail address -- or can recover it from what is posted with the instructions in my .sig below.
    Good Luck,         DoN.
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If the lamps fire on 240, I can't see any problem just using 240V. If they don't ignite, then boost may be necessary. GE seems to say their magnetic 277V ones are rated     "Line Voltage Regulation (+/-)    5 %" but not sure what that means... less light output at lower voltage? Won't work at all?
Test a unit for 24H and see what temp the ballast is...
[There are no 240V one listed but the newest electronic ones are often "120-277"...]

While the 277V ballasts were manufactured to run from a 480 wye to neutral; I can not believe that they have one leg of the input grounded. But measure with an ohmmeter, and be sure. And do a bench test with a unit safely fused.

Measure. Best way would be a test setup with a 120V -> 240/277 transformer, and then put a Kill-A-Watt <http://www.p3international.com/products/special/p4400/p4400-ce.html in the 120 supply. This will tell you the true watts of a fixture, and the current & power factor. {Watts * time is what you pay PGE for; but the transformers are limited by current....

Read what DoN said about relays. Control the fixtures with relays to gain the flexibility you want. Note the tradeoffs in lamp life with cycling. <https://en.wikipedia.org/wiki/Electrical_ballast#Fluorescent_lamp_ballasts
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