It's a Russell-Hobbs plate warmer/heater. Element has failed. Not a proper one-piece rigid element, but a 1.5 metre (approx - hard to measure in place) length of spiral-wound heating resistance wire encapsulated in ceramic material. It's secured at several insulated and heat-resistant points, has an insulating shield between it and the underside of the hotplate, and white mineral heat-insulating wool between it and the topside of the base of the unit.
Although it looks tacky inside, it is (or was) very good functionally.
The resistance wire is silver-soldered to the supply tails (the live tail passes first though the off/thermostatic control switch/rotary control). The thermostatic control is (was) very good.
The heating resistance wire has broken a number of times - possibly owing to bumping the unit about when putting it away after use when not fully cooled down. Each time I twisted the broken ends together and it worked again for several months, then broke again, sometimes in a different place. That was despite handling the unit with "velvet gloves"!
The rated voltage is normal 230 Volt AC. Rated wattage is 400, so consumption is around 1.65 Amps.
The resistance of the element is about 140 Ohms (377 Watts at 230 Volts/394 Watts at 240 Volts). As already mentioned, the length of the encapsulated spiral wire is about 1,500 mm (four straight runs plus the three points where the wire is bent round to continue in the opposite direction).
If the wire is nichrome, which seems pretty certain, the electrical resistance when heated must be similar to what it is when cold. If so, the readings I have taken look plausible when compared with the rated wattage.
The ceramic encapsulation has broken at most of the bends (though it was not always at these points that the resistance wire broke), so electrical safety looks questionable. However, the metal base and heating surface are earthed and the unit has never shorted internally/blown the 2 Amp fuse in its standard mains plug.
Russell-Hobbs (which is not the old firm of that name now) were completely unhelpful. They sell no spares for this heater, even though the plate warmer is still on sale.
SO
Where can I get spiral-wound heating wire encapsulated in ceramic or, better, an alternative less inflexible material such as fibreglass, with a resistance of about 90 - 100 Ohms per linear meter so as to achieve 140 to 150 Ohms from a 1.5 metre length? I have searched via Google to no avail at all, so wonder if one of the DIYNOT community might know.
I prefer to repair potentially usable appliances rather than buy new ones, so I live in hope!
Many thanks in advance for the help that I need,
CarlH
Although it looks tacky inside, it is (or was) very good functionally.
The resistance wire is silver-soldered to the supply tails (the live tail passes first though the off/thermostatic control switch/rotary control). The thermostatic control is (was) very good.
The heating resistance wire has broken a number of times - possibly owing to bumping the unit about when putting it away after use when not fully cooled down. Each time I twisted the broken ends together and it worked again for several months, then broke again, sometimes in a different place. That was despite handling the unit with "velvet gloves"!
The rated voltage is normal 230 Volt AC. Rated wattage is 400, so consumption is around 1.65 Amps.
The resistance of the element is about 140 Ohms (377 Watts at 230 Volts/394 Watts at 240 Volts). As already mentioned, the length of the encapsulated spiral wire is about 1,500 mm (four straight runs plus the three points where the wire is bent round to continue in the opposite direction).
If the wire is nichrome, which seems pretty certain, the electrical resistance when heated must be similar to what it is when cold. If so, the readings I have taken look plausible when compared with the rated wattage.
The ceramic encapsulation has broken at most of the bends (though it was not always at these points that the resistance wire broke), so electrical safety looks questionable. However, the metal base and heating surface are earthed and the unit has never shorted internally/blown the 2 Amp fuse in its standard mains plug.
Russell-Hobbs (which is not the old firm of that name now) were completely unhelpful. They sell no spares for this heater, even though the plate warmer is still on sale.
SO
Where can I get spiral-wound heating wire encapsulated in ceramic or, better, an alternative less inflexible material such as fibreglass, with a resistance of about 90 - 100 Ohms per linear meter so as to achieve 140 to 150 Ohms from a 1.5 metre length? I have searched via Google to no avail at all, so wonder if one of the DIYNOT community might know.
I prefer to repair potentially usable appliances rather than buy new ones, so I live in hope!
Many thanks in advance for the help that I need,
CarlH
