any suggestions for a fast mains changeover system

[[email protected]]

Yeh you all guessed fairly close ...replace the weed with a 1000l
fishtank and a kw of MH lighting ....Growing weed with MH's is a waste
of good lighting!
I need to changeover between peak and off peak.

 

[Russ]

Ahh, a hydro setup then

Yeh you all guessed fairly close ...replace the weed with a 1000l
fishtank and a kw of MH lighting ....Growing weed with MH's is a waste
of good lighting!
I need to changeover between peak and off peak.

 

[amstereo]

not just weed. Mind altering blood cooking, liver bashing, all 'rolled up'
in to one hell of a fry

 

[Phil Allison]

"The Real Andy" <

"amstereo" <

Come on Phil, he is only young.

** No excuse for posting bad advice and refusing to be corrected.




......... Phil

 

[Bob M]

I need to make a cct to change over between 2 mains supplies (they are
in phase). The hard part is it needs to change over within around 5 ms
which makes changeover relay out of the question. The current switched
will be about 5A @ 240v (metal hallide lights). Ive tried a changeover
relay but the nature of the lights is they will drop out for about 5
mins with an interuption of about 15ms or greater.

What type of ballasts are you using- electronic or regular
transformer? If you are using electronic ones and you are reasonably
handy, then it would be a simple matter to modify them to bridge the
required relay cutover time. The input mains are rectified and
filtered to produce a DC voltage which is then switched at a high
frequency (~20KHz) through a toroid transformer to drive the lamp. The
switcher is electronically current limited to control the power fed to
the lamp.

All one would have to do is increase the input filtering capacitor(s)
to bridge the time required for a DPDT 240 volt AC relay to switch
between the off-peak and regular feeds. The 240 volt AC coil would be
permantently connected to the
off-peak mains. The relay tongues go to the load (ballasts in this
case). The normally open contacts go to the off-peak mains feed and
the normally closed contacts go to the regular feed mains.

Many years ago, I did a similar modification to several PC power
supplies at work once to compensate for a rather slow to kick in UPS
we once owned (really ugly unit). It was eventually replaced with a
true on-line unit.

Cheers from Canada

Bob Morgoch

 

[Mark van der Eynden]

I need to make a cct to change over between 2 mains supplies (they are
in phase). The hard part is it needs to change over within around 5 ms
which makes changeover relay out of the question. The current switched
will be about 5A @ 240v (metal hallide lights). Ive tried a changeover
relay but the nature of the lights is they will drop out for about 5
mins with an interuption of about 15ms or greater.

What about putting two diodes (parallel / back to front) between the
mains and the off peak mains? The voltage drop ensures the Off peak is
used when available.

Of course 1. Only the lights can be 'off peak' and 2. The phases must
be the same.

Cheers,

Mark.

 

[David Sauer]

Yeh you all guessed fairly close ...replace the weed with a 1000l
fishtank and a kw of MH lighting ....Growing weed with MH's is a waste
of good lighting!
I need to changeover between peak and off peak.

You want something that will run off the off-peak meter when there is
power available, and when your supply componany drops it off in peak
period you want it to automatically swap back to use the peak meter?

You do know most supply authorities only allow you to connect
appliances to either peak or off-peak and not have _automatic_
change-over devices installed.

Some will allow manual change overs (a switch) so that people can say
have their swimming pool cleaned with the filter on, in a peak time
when power would not normally be available to the filter.

 

[[email protected]]

Bob,
i wish i had electronic ballasts but unfortunately they are
magnetic. We pay about double for them as what you guys pay for them
over there...

 

[[email protected]]

Mark,
the idea sounds ok but i need isolation between the 2
supplies ... ie can't feed the peak back into the off peak supply or
the poor old diodes will be powering the hot water service as well
....they'd probably melt!

 

[amstereo]

I still like the collapsing relay idea that uses the off-peak to trigger it
with a larger non-polarised capacitor to fill in the blanks..

 

[Fat Crack Ho]

Any chance you're switching between hot water tarrif power and normal
residential tarrif when the discount tarrif isn't available?

 

[James]

..

Of course 1. Only the lights can be 'off peak' and 2. The phases must
be the same.

Cheers,

Mark.

G'day

Why dont you get some double strike lamps? These will refire quickly
after a short interruption in power supply, look up thorn or pierlite,
they should be able to help.

Would another option be to maybe have 2 lamps there? A metal halide
lamp isn't all that expensive but it may not be an elegant solution to
have 2 lights there. The rep from pierlite did mention some sort of
instant start metal halide lamp too but I dont know anything about it.

cheers
james

 

[Bob M]

What type of bulbs are you using (and ballasts for that matter)? About
7 years ago, I built 2 electronic ballasts for a good friend of mine
for his aquarium. Last time I spoke to him (July last summer at my
50th bday party), he mentioned they were still working fine. I can try
and dig up the schematics etc. if you wish. If my memory still serves
me (I'm NOT taking any bets on it) they were more effecient than
their regular counterparts and weren't too expensive for the parts.
The only hassel was the sourcing of the toroid transformers and the
winding of the coils.

Let me know if you are interested.

Cheers from Canada!

Bob

 

[Mark van der Eynden]

Mark,
the idea sounds ok but i need isolation between the 2
supplies ... ie can't feed the peak back into the off peak supply or
the poor old diodes will be powering the hot water service as well
...they'd probably melt!

In that case just add the relay back in.

Mark

 

[[email protected]]

The lamps i have are specifically aquarium lamps ..20k colour temp
(very blue / crisp white) and very expensive $150 ea (i have 4 of
them!)

 

[Ken Taylor]

If they're all you have to worry about why not put them on a UPS?

Ken

 

[David Sauer]

Any chance you're switching between hot water tarrif power and normal
residential tarrif when the discount tarrif isn't available?

He's already stated that elsewhere in the thread.

Why dont you just bugger up the relay in the meter box so that
off-peak is always available and never gets switched off?

 

[[email protected]]

Bob,
i'd love them if you can email them to me or something like
that. One ones i have a 250w radiums which actually run off a HPS
ballast. Take the delete out of my email address on reply!!

 

[[email protected]]

yep!! you got it!!!! ...when running 1kw of lights 14 hrs a day its
worth it ...not to mention 500w of pumps ... 18c/kwh peak vs 7.3c
offpeak ..per year it would be a few hundred dollars worth...

 

[[email protected]]

The inefficiency and expense of a 1.5kw rated UPS would make it a
large waste of money!!.. At the end of the day i'm just tring to knock
the power bill down on my lighting since its run for 14hrs/day