load ratings

[b1nuzz]

This is going to seem a really dumb question, but im still learning, so here goes:

 

A company who are in the theatre at the moment, have patched in the lamps as normal, but on some of them, put an extra lamp in the patch room, to act as a 'load manager'. Thats what he called it anyway.

 

What is this done for? it confuses me.

 

Thanks

 

Ben

[gareth]

Sometimes, older dimmers can't handle very small loads too well - e.g. practical table lamps, birdies, etc. If this is the case, you need to put a 'load lamp' in parallel with the very small load, to make the dimmer behave as it should.

[J Pearce]

Basic answer: If they are dimming low load lanterns or inductive loads (pinspots come to mind) the triac (main component of a dimmer) can malfunction, putting in a dummy load or 'load manager' can help the triac work properly.

 

More complex answer: Triacs need a minimum current through them to operate, this dummy load ensures the current through the triac is above the minimum.

 

[edit]

 

Beaten to it by Gareth

[b1nuzz]

cool. Cheers guys. had a feeling it was something like that. Just thought id better check. Can delete the topic now!

 

Ben

[Bryson]

Nope, we wont. We leave topics in if they have any useful info in them so that people next time can search. No need to delete perfectly good topics such as this one!

[Andrew C]

No need to delete perfectly good topics such as this one!

It also gives people the chance to expand on topics:-

 

Be very careful with ballast loads in dimmer rooms. It is sometimes not obvious what they are and, say, some Muppet hangs a coat over a stand when the light is off...

 

Been there, seen it, lots of smelly smoke. No serious damage, except to the coat!

[johnhuson]

On a similar topic of idiots with load lamps, once saw someone put the load lamp for a single ACL bar, in one of Vari*Lite's lovely plastic flighcases, boy did it melt.

 

To expand for those that don't know, ACL lamps are 28v and usualy eight lamps are run in series (often two bars of four lamps). For those occasions when you only want one bar of four lamps on a circuit, you have to balance that out with a 110v par lamp. Usually you don't want the load lamp in view, so depending on your situation you hide it in some way. On an outdoor festival stage it's often not that easy but I usually find having it under the stage with two bits of 181 gel or some black wrap in the gel frame does the trick!