What Can I Use To Make And Brake An Electric Motor Connection?

You omitted a key point of useful information--the temperature range you need.

temperature range for a burning charcoal. unfortunately, i dont know this.

That's not the point.

Are you cooking chicken of forging steel? We don't know what you are trying to do.

There has to be a point where the charcoal does what you want it to do.

Pick a spot on your contraption where a temperature sensor (Rixter #8) can detect the ideal heat and go from there.

"Charcoal burns at intense temperatures, up to 2,700 °C (4,890 °F). By comparison the melting point of iron is approximately 1,200 to 1,550 °C (2,190 to 2,820 °F). Due to its porosity it is sensitive to the flow of air and the heat generated can be moderated by controlling the air flow to the fire."

Charcoal - Wikipedia

Charcoal's max temp puts it above the range of many thermocouples. That can get expensive. Find a way of reliably correlating your charcoal's temp to some point nearby, and measure the temp there. Then look at the link Rixter provided and see what's available. Ultimately you temp measurement will result in a relay or contactor opening and closing to control your motor, or you could go with 'proportional' control - varying the motor speed over a range - if that would better suit your needs, I dunno.

.....and what type of motor he wants to use.....and the voltage he wants to use......and possibly the current draw......and he may want speed control of the motor in such an installation.

Put a thermostat of the outside of the chamber, or somewhere that it can sense the temperature, and adjust it so that it controls the motor to give the desired result..

You might want to try googling for a circuit or a thermostat. (If you know what "googling" is)

You might get more help if this were placed in the correct category.

Are you a friend of coolyaar?

Oh, it's "make and break". not brake.

If the current is too high for a standard thermostat then you can add a contactor to switch the high current motor load and connect the thermostat to the contactor control coil. Thermostats are dead simple to program, either with a temperature dial or through a simple key pad.

You will likely need an electrician to do this for you to get the wiring right and perform the work in a safe way and legally complaint way (especially if this is for a commercial or industrial application).

"Legally complaint"?

A typo, should be legally compliant (otherwise a contradiction in terms).

Disclaimer - I'm a railroad guy; don't burn your house or factory down trying this.

Operating characteristic of your fan motor?

Supply voltage? How much amperage does the motor draw when starting and running? This will determine whether it would be more practical to use a parallel bank of switching mosfets or mosfet controlling a contact relay?

Obviously you would want the circuit to fail safe - motor not running?

Use a high temp thermocouple and measure the output voltage at the desired temperature? Or perhaps an IR sensor.

Get out your breadboard and set the input voltage = to thermocouple output at desired temperature. Put a variable resistance in series with the input voltage where the resistance is high enough to keep the MOSFETs you will be using from switching states (on/off). Determine at what resistance the mosfet switches.

Use the output from your resistance damped thermocouple (or IR) output to bias the control mosfet(s)?

You may want to put some hysteresis in the control circuit.

Another method is to use reactive control of your motor to maintain optimum speed of the fan for the given temperature you want to maintain. This will ramp your fan speed up and down instead of turning it on and off.

Umm, based on Loanky's posts I think you solution and terminology is way beyond his current understanding.

With all due respect, if people cannot come to this forum for technical advice, what good is it?

I am not saying you shouldn't (far from it); I just sense that, based on the information the poster has provided and the way he(?) has worded it, it sounds like this solution (while valid) is possibly too complex for him.

If he doesn't know what the temperature is supposed to be, is he going to understand what a MOSFET or control loop hysteresis is?

While that might be the case, I think it could've been worded differently. But that's just me.

Well, it was clear in my mind when I wrote it (except for the missing r).

I didn't want to unintentionally sound condescending to this new CR4 poster.

"... (except for the missing r)"

I didn't notice. I've a profreader, so I've no excuse.

A lot of what I see online relating such threads as this one is not always that someone doesn't have an understanding of what they are wanting to do, but they seem to have some very poorly reasoned-out justification that whatever they are doing is some top secret world changing idea they can't allow anyone to know anything about.

Either that or they know that they are chasing a bad idea and don't want to have to deal with the reality that, by giving up all the relevant details that will lead to them getting a workable solution, in the act of doing so their less than adequately thought out design is going to get a pretty harsh critique (showing they spent way too much time and money on a concept that five minutes of basic online searches and reading on their subject at hand would have shown their approach to be a bad idea and design as well).

No harm in helping the bloke out. GA

I may consider this later but I need information on how to set it up, connect and assemble it to make it work as intended. All want is a DIY guide..

Thanks.

A PID type temperature controller with a J or K type thermocouple can work up to around 2300 F.

Past that indirect IR would be a reasonable method to look at.

That was my first thought, indirect IR or non-contact temperature measurement.

It would be nice to know what the OP is doing, is this to heat a residence? or something industrial or otherwise?

If you want to use a PID cobtroller, a 3 phase inverter (or a 3ph VARIAC) is required, while for an ON/OFF controller a contactor is enough.

How do you justify the need of the PID controller for this application?

Because for whatever reason you can buy a PID controller and set it up to work as a basic on/off temperature controlled relay for far cheaper than you can buy a basic programmable process control thermostat that by design only does basic programmable on/off work.

I have a bunch of PID controllers laying around just for that sort of applications because they were both cheaper to buy and have more functions than any normal basic programmable process control thermostat.

As of now my go to devices for general purpose temperature control are the MyPin TA4 PID temperature Controller being they have every major function and feature of any standard PID controller but for 1/4 - 1/10 the cost (~$25 each) and in even some rather harsh applications they have shown themselves to be as reliable or even more so than their higher cost big name brand counterparts.

How do I program the PID controller and connect it to the motor to switch it on/off depending on the set temperature. Please, can you explain this? How will I make it to work as on/off temperature control. What other device do I need to use and how do I set them up? Can you explain what the PID controller does in this senerio to achieve the on/off temperature switch. I've read some things about this controller but rather gets complicated that I have to ask myself if it would actually do what I want. I also saw some article about connecting the PID controller to a thermocouple but no satisfactory details on how it will work for my own application.

Thanks for your contribution and sorry for the late reply. I barely come online these days.

A laser thermometer springs to mind as a non-contact way of measuring temperature.

loanky was any of this helpful? I get the feeling we have perhaps offered you temperature control solutions that are rather more complex than you were hoping for.

Can you give us some feedback please? Did these answers make sense?

If not, what are you actually doing with the charcoal? Is this for a home cooking application, a small business, etc.? What is your budget for a solution?

The more information we get, the better we can offer a suitable solution to you that you can understand (unless we have already done so).

While I immediately think of the quarter size thermostatic switch in my wood burning stove that turns the blower fan on/off, and is mounted near the exhaust smoke stack. I see the crew has succeeded in making the easy difficult.

You may wish to use some asbestos or high temp insulated wire for hook-up to the switch.

I was recently thinking of adding a desk top computer waffle fan to my barbecue grille for those days when there is not enough wind, or I want better air control. The waffle fans are quite forgiving.

I'll try to be more timely, but this is the first alcohol I've had in quite some time.

The coyotes are yipping in the Arizona desert, time to tease the buggers.

If your trying to put the thermostat where it is too hot, then you may need to put a stove pipe around your stove pipe to isolate the switch from excessive heat. This will slow down the reaction, make temp swings larger.

Will the type of your thermostat able to withstand temperature around 400 celsius high enough to roast or fry-dry a mash of food in a pot? I intend to place the thermostat around the exterior of the frying surface but I may consider placing it around the exhaust of the machine so that I wouldn't require a more higher capacity thermostat and still be able to correlate the temperature of the exhaust to the temperature of the frying surface which I'm trying to monitor. I would like to know what type of thermostat you are using, where I can get it from and how you set it up to work for you. I would appreciate if you can explain how the whole control process works (the working principle). Thanks!

PS: I have decided to attach the picture of the machine's design but I have not yet included the blower. You can see the gear trains which control an arm that stirs the food mash.

There are other ways to regulate the combustion. For hundreds, or even thousands of years the temp. has been regulated by either opening or closing a damper on either the inflow or the chimney. Make a simple bypass valve and place a graduated quadrant on the damper arm. You can then mark the quadrant with temps observed and measured while in use. Very rough and ready but without knowing the sort of precision you are after it's an idea worth throwing in the mix.

Jim

A thermometer/Thrmocouple/hand helded IRScanner, and an On / Off switch will work just fine. No complicated circuits, MOSFETS, designing, clamping, screwing, glueing. Just take a reading of the coals at the right glow you require, (temperature is done, you have a back up reference point, you know the glow required, you have a temperature).

1. When you see the glow is approximately that which you require, switch off the blower. You can use the IR scanner as a back up check for the temperature.

2. If the temperature is sensitive, use the IRSc or the thermo couple to get the right temp, then switch of the blower.

3. Alternately, a hand held or foot operated bellows will save all that hassle for you. No electrics, no hassles.

Still don't know if the device is to fry chicken or cook steel.

Important is an coorect use of the charcol, when CO is produced in a closed room people will get killed. In Germany recently 6 people did just now die in a garden house. ......

The electric components + correct wiring are also not the negligeable facts.

Buy a certicated oven or grill.

You could use a thermocouple and distance it from the actual combustion process and measure the temperature at a point in the exhaust pipe where it has cooled to the point where it won't melt the measuring equipment. Maybe a thermostat in the 500 degree range /thermostats-switch/electromechanical/3583

An IR sensor, a Arduino board, a relay.

Based on the comments I've read so far, I can see you all are ready to help. So, I've decided to update the post with more facts about what I'm trying to achieve. Below are some points:

1. The project is a final year project.

2. The project is about a design of a machine that can mechanise the process of drying/roasting/frying of cassava mash to make gari.

3. The machine has a heating chamber and requires a blower with direct connection to a single phase electric motor. The purpose of this blower is to supply air for combustion of charcoal so it can stop when the charcoal is hot enough for the frying process. So, what I need is a device, may a sensor, that can sense the temperature and break electric motor's connection to supply of power when temperature is high enough. I want the whole process to be automatic so that you wouldn't need to manually switch off the motor. I'm sorry if I sound like I have little knowledge, that's because it's true.

4. I want a recommendation for what equipment/material I can use to automatically make/break motor's connection to supply of power depending on temperature measurement (as against some comments suggesting regulating the speed, I want the motor to switch on and off accordingly) and how I can achieve this. For comments suggesting PID controller (I have read some things about this devce though my knowledge may not be accurate enough), I thought PID controller will only try to keep set value constant by probably trying to control the temperature without actually switching off/on the motor? (I don't need something complex, what I want is just a device that will automatically disconnect motor once a set temperature is reached. If PID can do this how do I achieve it?)

5. I would also appreciate it if you can suggest a reasonable temperature that should suffice for drying/frying/roasting process of any mash (cassava mash in this subject).

6. I want to know if there's just a mechanical thermostat (pneumatic, bimetallic strips, etc) that has high temperature ratings and whoose temperature can be set such that it response to the set temperature would be disconnecting a circuit

7. I need help on how to achieve these objectives with whatever equipment or device you are recommending.

8. I would appreciate economic friendly suggestion.

Thanks for your audience!

Still no pertinent information.

OK , now describe how many gari you want prepare, for example kg per day, tons per day or milion tons per year? Then let your granmother explain the procedure to make the small quantities, or a professional cooker can tell about manufacturing the larger quantities. May be you want visit a manufacturer exporting to all coontries? The heatnig systems will be different ...... and the control systems, too.

I now see that the reason you haven't provided any pertinent information is because you don't know any.

You need to establish quantifiable specifications. To do this you MUST measure quantities, time, temp. You must also establish a set, repeatable process. Why?

Then you will be able to better answer your own questions.

Jim

I still don't understand what other information you guys need. Jack of all trade, in his reply, ask for futher information which I provided answer to all the questions he was asking. You said I don't know what to do. I wouldn't have come here, perhaps register here, if I have the knowledge of what I needed, in terms of equipments and how to set them up. I clearly stated that I would like to make a motor switch off when certain set temperature (a high temperature in the range of 400 to 600 celsius) is attained and I asked for the equipments I needed to achieve this and how to set it up. I asked whether there's just a simple thermostat that can withstand such high temperature and has a functionality for setting my desired temperature such that it's response to the temperature would be striping of electric motor's connection to supply of power, or if I need a controller that requires an input from a temperature sensor (thermocouple) and that will compare this input to a setpoint and break motor's supply of power once the temperature is attained. I clearly do not know how this will work or how to set them up and that's why I came here for advice and idea hoping I'll get help. I expected to get advice based on equipments I needed, how this equipment will work to achieve this and how to set them up. Perhaps if the choice of these equipment will depend on certain information, I expected to get information on equipment specifications and the factors that may affect my choice of this equipment, so I could make selection based on my own requirement.

Your next post (#41) is a good start point. This is the first time you gave a temp (#40) so that helps.

Jim