questio answer

[Spark123]

You mean like one of those booms they use in a TV studio?

 

[tim west]

You mean like one of those booms they use in a TV studio?

A Camera Crane like this:

Sorry for the poor picture it's the only one I can find of the Heron, If you can make it out the cameraman is sitting on the platform in the centre of the photo and you can just make out the jib along with hydraulic piston for lift.

 

[ricicle]

Used to work with 230v 3 phase motors, transformer stepped down

I have used 'Dual wound' motors where they can be connected 415v star/240v delta.

This enables the motor to be controlled via a single phase input (240v) /3 phase output (240v) invertor

 

[tim west]

Used to work with 230v 3 phase motors, transformer stepped down

I have used 'Dual wound' motors where they can be connected 415v star/240v delta.

This enables the motor to be controlled via a single phase input (240v) /3 phase output (240v) invertor

Yes with the invertor technology possible these days they (BBC) could have run many of their camera cranes off of these supplies ,just didn't have that technology then.

Got involved mid 80's in a project using a 3 phase(415v) to 110v DC invertor to control a "Mole" Richardson Crane although had to devise a means of altering the current flow to enable reversal of the motor when needed, this I achieved by designing a bridge rectifier arrangement across the field winding that forced the current to stay in one direction when the output poles from the invertor connected to the armature changed polarity, it worked very well with a smooth take off which was essential.

Unfortunately the technology came just too late as the cranes had all but had their day as they are more and more being replaced by single operator ones (Technocrane, Jimmy Jib etc) to cut labour costs.