The Craftmans Shop > New from Old

Titivating a Pottery Kiln

<< < (2/5) > >>

vintageandclassicrepairs:
Hi All,
Andrew,
A dodge we used to use when getting old open frame 3 phase motors that had very low resistance to earth back into service was to connect the winding's in series and then connect a 220v supply across them.
It is usual to see the resistance to decrease again as the plot cools down, especially in Winter time when some of the moisture in the air is re absorbed,  a few cycles of heating will sort it out

John

awemawson:
This morning the leakage resistance between Earth and Neutral was down to 1.5 M ohm having been warmed by a 100 watt light bulb over night, so I deemed it 'safe to try'.

A quick temporary connection to a 16 amp commando plug, and off she went without drama thank goodness. The Cromartie controller still seems to work, and it looks like the set point is at 200 deg C, which is sensible if I was last melting out wax. Very quickly the temperature got to set point with an overshoot to 215 deg C as might be expected.

I'll leave it on this morning to dry out - each phase is drawing roughly 18 amps when on (yes I KNOW it's on a 16 amp service!) but it's not on much of the time - cycling on / off on the controller.

I was surprised to find that the HN07RN-F 5G1.5 flex for my 16 amp extension cable is actually rated at 19 amps in free air.

Pete W.:
Your troubleshooting seems to have indicated moisture in the kiln lining.

Still, if it were mine, I'd have a go at those three porcelain terminal blocks with a toothbrush and some washing-up liquid.  (Switch off & disconnect first!! )

Maybe this comment is motivated by envy - the volume of that kiln is only about a couple of orders of magnitude smaller than the volume of my workshop!!

It looks to be a handy bit of kit. 

awemawson:
Pete, the whole inside will be re-wired when I've proved that the lining has dried. I did give them a bit of a wipe but whatever it is it isn't just sitting there!

By the time the walls of the kiln are taken into consideration it's not that big inside actually.

It's been cooking all morning ranging from 195 to about 210 deg C while I get on re-building the 90 degree powered tooling adaptor for the Beaver CNC lathe

awemawson:
Years ago, the test to see if someone was still breathing when near to death was to hold a mirror close to their mouth, and the moisture will condense as a mist.

. . . well it works for damp kiln linings  :clap:

Holding a 6" square glass mirror tile over the ceiling vent, dead obvious that a fair amount of moisture is being driven off    :thumbup:

Navigation

[0] Message Index

[#] Next page

[*] Previous page