01-06-2015, 02:47 PM
This is a Means to an End 
For some time I've wanted a Load suitable for testing HT Supplies - I'm fed up with cobbling together strings of Resistors. I considered all sorts of exotic options - Valves, Transistors, FETs - but in the end decided it would be better to have something simple and reliable.
So, a couple of strings of Resistors seemed appropriate, say 10 x 1k for the usual Valve Supplies and some 10ks for typical Battery Set supplies.
Something like this:-
A sweep round the usual Suppliers showed that 300 x 200 x 6mm SRBP was readily available. Add some cheap Terminals and 5/7W Resistors and do a Drawing to see if it all goes together.
Looks promising.
Not wishing to have the live Resistors exposed I decided to add a Perforated Steel Cover to the back. In order to attach it I bought some 10mm Steel Angle from B&Q.
The first job was to make a Frame to attach the Back' to the 'Front' using the Steel Angle. I considered Mitres for about 3 seconds but they're never been my forte - I usually finish up with half the ends cut the wrong way round. Brazed Butt joints were the order of the day followed by some fettling.
Next a 'Cage' for the back. That was just a matter of cutting the corners out of a piece of Perforated Steel and bending it up with the aid of a couple of pieces of Hardwood and clamps in the Vice. That fits inside the Frame and was tacked in place a few strategic Brazes. That's where my newly refurbished Metal Shear came in.
To be continued ....
Alan
For some time I've wanted a Load suitable for testing HT Supplies - I'm fed up with cobbling together strings of Resistors. I considered all sorts of exotic options - Valves, Transistors, FETs - but in the end decided it would be better to have something simple and reliable.
So, a couple of strings of Resistors seemed appropriate, say 10 x 1k for the usual Valve Supplies and some 10ks for typical Battery Set supplies.
Something like this:-
A sweep round the usual Suppliers showed that 300 x 200 x 6mm SRBP was readily available. Add some cheap Terminals and 5/7W Resistors and do a Drawing to see if it all goes together.
Looks promising.
Not wishing to have the live Resistors exposed I decided to add a Perforated Steel Cover to the back. In order to attach it I bought some 10mm Steel Angle from B&Q.
The first job was to make a Frame to attach the Back' to the 'Front' using the Steel Angle. I considered Mitres for about 3 seconds but they're never been my forte - I usually finish up with half the ends cut the wrong way round. Brazed Butt joints were the order of the day followed by some fettling.
Next a 'Cage' for the back. That was just a matter of cutting the corners out of a piece of Perforated Steel and bending it up with the aid of a couple of pieces of Hardwood and clamps in the Vice. That fits inside the Frame and was tacked in place a few strategic Brazes. That's where my newly refurbished Metal Shear came in.
To be continued ....
Alan
