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5

It matches rectifier Case 175-03 or 253-03 used on SCR's with an obsolete P/N made in 1987 week 39 (8739). Appears to be rated for about 25A with 4 switches to serve as 2 half-bridges for 2 loads with variable phase or ON/OFF control. It takes 2 SCR's to make a Triac. Also obsolete from 1987 is the latest cell phone. My friend had one of these.

0

I am planning to split the heating coils into three separate sections with independent thermocouples and controller setup, where each section would be wired as an independent 3 phase heater. Would this design work? Probably. You will have (mostly radiant?) heat transfer between the heaters and your workpiece, and conductive heat transfer within the work ...

0

I do suggest you to not use separate controllers for each phase, rather turn all three on/off heaters at the same time using three phase contactor and 3ph protecting circuit breaker. Imbalanced high loads on 3ph network may cause several problems.

1

I have a 'DMM with K-type thermocouple input', and a K-type digital thermometer. The DMM reads reasonably accurately over the 15-30C 'lab ambient' range of temperatures, with increasing error above that, until it's many many degrees out at 100 C. The digital thermometer, in the same size case and not costing much more, is quite accurate at 0C, 100C, and all ...

4

There's a decent chance your multimeter does not bother to linearize the thermocouple curve. The uV/°C is less between 0°C and 100°C (40.96uV/K) than between 500 and 600°C (42.61uV/K) so you'd expect some sag at the 100°C point if they just average out the errors over the 760°C range. Most older design multimeters are very linear (can't speak for yours), but ...

4

If the type K probe is made properly you ought to get good results to +/- 0.5'C. Like any ADC calibration, you test for errors in offset, gain, monotonicity, linearity and dead-bands and if desired the RMS integrated average squared error (IASE) for every value. Find the value that is not affected by gain or temperature of the sensor, perhaps 0'C then null ...

0

As of June 2020, you can know with good accuracy. The accepted answer is not completely correct anymore. All the information is provided in https://github.com/cpetrich/counterfeit_DS18B20 which also links to Arduino sketches which can tell you, based on the expected data returned by the chip, whether your sensor is original or not. The clones do not fully ...

4

Here is an approach to thermal isolation while maintaining some mechanical strength -(the chip is an ovenized buried zener voltage reference- it would have a urethane foam insulator over it in actual operation): As well as the wide routed slots, notice the thinner ones to the left and right and the slots to the top and bottom. The copper, even 34$\mu$m ...

2

From what I've seen in a room thermostat (0.1°C resolution), the traces were as thin as possible. The PCB had numerous air gaps to isolate the sensor from the heat generated by voltage regulator. The sensor was placed at the corner of the board and there were holes milled into it to limit heat passing through the board. No copper pour in that area. So little ...

0

I don't know yet if this could be the optimal or final solution. But I have realized when overcurrent starts at my circuit. By the moment during a week under test I can "say" when it happens: when I handle wires driving other logic state value and push one of them into the GPIO input pin hole. My python control sw: configures bank A as inputs with ...

2

Do some more reading of the datasheets. Devices like MOSFETs can be offered in several packages, from large TO-247 style to SMD with a small metal tab that solders to the board. So the package used determines the amount of metal area to dissipate heat. For many popular MOSFETs the change shows up as a modified part number, with the base part number the same. ...

7

There's no significant voltage drop because there's no significant current flowing - thermocouple amplifiers have a very high input impedance. You also need to remember that a thermocouple sensor does not generate a voltage at the sensing junction - the voltages are generated along the length of the wires and the voltage generated along each wire depends on ...

14

Wire cable resistance is insignificant when compared to the input impedance of the amplifier which is so high that the wire doesn't affect the measurement. For example, the LT1052 (which would be great for a thermocouple) has a 30pA input bias current, which corresponds to over 100MΩ of resistance. Wire cable even in the 100Ω range with a 30pA current would ...

5

Thermocouples used for temperature measurement don't suffer much voltage drop because the thermocouple interface electronics don't draw any current from the thermocouple (ideally, they don't draw any at all). You may have problems with other effects, but voltage drop should be negligible.

2

The coiled filament operates at 900°C when powered with 10 watts Only the filament gets hot. Which is wound around a ceramic rod suspensed on two steel poles. Before this 10 Watt conducts down to the solder joints of your connector it needs to heat the metal and ceramic base which you can inserted in a heatsink. I suspect you can't solder the steel pins, so ...

2

They claim it can be mounted on a PCB. Easy enough to test it on a bit of perf board, though the manufacturer should be able to advise. Definitely put the reflector shield in place. I suggest using a couple of Mill-Max socket pins. It's only 11W, so aside from IR radiation heating the PCB, it's not necessarily much worse than an 11W power transistor. Note: ...

2

No, there are no ferrite materials that thermally degrade at 100°C. Even if heated above their curie temperature (this is the temperature a magnetic material looses its magnetic properties entirely and behaves similar to an air gap. Or for permanent magnetics, this completely demagnetizes them), virtually all ferrite materials will regain all their ...

2

The best way would be to break the glass envelope and use the filament as an RTD. Tungsten has a positive temperature coefficient of 0.45%/K, similar to copper. Under those conditions the filament would run just a bit above ambient temperature. It isn't essential to remove the envelope but it would help couple temperature changes to the filament. Some lamps ...

3

Since it is a theoretical question, and no one can prove a negative, I'm going to say yes. You could determine the ambient temperature by observing changes in an incandescent light bulb's current. I apologize for not knowing the source, but a wise person once said "Everything is a temperature sensor but some are better than others". When the ...

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