Hello, I need some info on European 240v HID choke ballasts for a project i'm going to do. I have 3 questions.

1) Can you use a standard hps/mh choke ranging from 35 watts to 1000 watts to limit current to lets say, an appliance? (Without capacitor and igniter of course)

2) Can you combine ballasts to run 1 lamp, with capacitors still connected? (Ex, Combine a 200w ballast and a 50w ballast to run a 250w lamp WITH both sets of capacitors connected from each individual ballast? The uF values would add up.)

3) Will Probe start lamps work on PSMH/HPS Choke ballasts and vise versa?

4) Will chokes run on 60Hz

1. Appliance don't requires current limiting.
2. I don't know. Capacitor in chokes, are required only for PFC and don't affect lamp performance.
3. Never operate probe-start MH lamps on HPS/PSMH equipment. The lamps would be overdriven/distroyed.
4. If the choke don't states that it is for 60hz, but only 50hz, the different frequency can damage it.

You can, but what is the point ? (Are you trying to do something that is better done in another way ?)



Watts dont add up, you have to match the resulting current to the lamp requirements

Actually when the arc voltage is the same as with the intended lamp, then Watts do approximately add up. Good example is 2 40W Fluorescent chokes for 80W Mercury lamp

When the ballast is working with something other than its intended lamp, with different arc voltage, it will supply different current than it would to the original lamp. To not overload the ballast, only use it with lamps that have the same or higher arc voltage

Capacitor values would approximately add up as long as the currents are what the ballasts were intended for, but otherwise its only approximate (though not too far). Ideally it would have to be recalculated in this case. Anyway, the capacitor does not affect anything except line Amps, so you can skip it altogether (for NPF) or put in anything (adding up the values would be fairly close to HPF)



They might, but measure the current to see whether it is about right after the lamp warms up. Also if the probe does not start by itself (if 240V is less than the OCV of the proper ballast for this lamp), you may need some "weak" ignitor



At 60 Hz the ballast reactance will go up by a factor of 6/5x (1.2x), while wire resistance stays the same. As the ballast impedance is mostly the reactance, it will be affected by close to and somewhat less than 6/5x

This means that at 60Hz it will deliver lower current to the lamp than it would at 50Hz. Exact current varies with specific ballast and lamp, but expect it to be somewhat above 5/6ths of the rated current

Using 230V rated ballast on 240V might counteract this, and on 277V might actually get quite close to the correct current, or a bit over

On question 2, its not quite that simple, just adding 2 different wattages together to get, say, 250watt, is done for some lamps on European gear, (the 700watt MV being an example), but you have to know the specific running voltage/current for said lamp, and then try to match each ballast, (and their running specs), the best you can, and a single capacitor is ok for most set ups, providing it covers the PF for both ballasts together.

A bit off topic, but do the European 700w mercs run directly off 240v chokes (arc voltage of 120 ish)?

I think yes (That the european 700W MVs operates directly from 240V chokes).
European lamps with lamp current higher than 230V, usually operates from 415V 3PH chokes and not from autotransformer ballasts.

Yes they do for 240, some manufacturers had a single dedicated 700watt ballast, but most UK installations of 700watt MV were done by putting a 400watt and 250watt MV ballast in parallel with each other.

Thanks for all replies! For question 1, I think it was a bit misunderstood, but what I meant by ballasting an appliance, I really meant: Could you use these 240v chokes to ballast, lets say an MOT so it doesn't self destruct? Also would it ballast it on 60hZ if the choke says 50hZ?

 

Chokes that designed for 50hz only, may be damaged by 60hz mains frequency.

Chokes that designed for 50hz only, may be damaged by 60hz mains frequency.

I, and other members here, have run 240v SOX ballasts on 60hz supply

Chokes that designed for 50hz only, may be damaged by 60hz mains frequency.

Not true, plain and simple

Chokes that designed for 50hz only, may be damaged by 60hz mains frequency.

Would this be true for autotransformers? As Ash said, 60hz will not damage a 50hz choke but could it damage an autotransformer?

Normal autotransformer - Not at all

Stuff that have capacitors and leakage shunts - Will change its operating characteristics, so while the 60Hz itself does not damage the components, it may cause higher currents in the affected parts of the circuit (such as through the capacitor) and things might work off-spec, at higher power dissipation and such. Not allways, must test each case whether the resulting currents and heating are ok or not

The opposite - 60Hz gear on 50Hz - is more of a problem :

 - Inductive reactances go down, so for the same voltage, higher current will go. This may or may not be acceptable

 - Cores will go closer to saturation on 50Hz, so higher core losses for the gear, and potentially higher copper losses too if the saturation leads to excessive currents in the coil. Some gear may not be a problem, other (especially things that are marginally small core even for 60Hz, like cheap yardblaster ballasts..) may very well be

If there is a problem of overcurrents and such, it can sometimes be corrected by changing the voltage. For plain inductors, the rule of thmb is same V/Hz, so for example 240V 60Hz gear may complain on 230V 50Hz, but 277V 60Hz gear will be often just fine as the too low voltage makes up for the wrong frequency

So if I were to short out a 250w ballast thats rated for 50hZ, What would I get on 60hZ and how can I fix it?

I actually tried powering a 25w incandescent lamp on a 35/55w ballast at 120v and it ran at about half power. Is this because I ran it on 120v and not 240?