I have a heating element and 15 volt transformer which I have converted to 26 volts DC that run 24 volt DC brushless motor with 0.18a. I have connected the heating element and 15 volt transformer to one mains and Both the heating element and the fan have controls. My problem is anytime I turns on the mains and set the controls on the heating element to high, then the air that comes out of the brushless motor becomes low, but when I set the controls on the heating element to low then the air from the brushless motor become high. Any help will be highly appreciated.

 

draw a schematic please

 

Obviously, you are overloading the transfomer when the heater and fan are both turned on high.
Measure the voltage dropping to see it.

 

15vac converts to 21vdc maximum, even lower when you apply the heater load.

 

Maybe the value of the rectifier filter capacitor is too low for the DC to remain at maximum.

 

You need at least an 18vac to 20vac secondary.

 

You have a heater and it's controller connected to a 15V transformer.
Also you are running an up-converter doing 15Vdc to 26Vdc in order to run a 24Vdc brushless fan
and it's controller that is usually drawing 180mA. You want constant CFM but noticed the fan speed slowing opposite of how you want it to.

Because of the variety of modules and applications there are many choices with slightly different wiring.
Can we narrow down the choices ? A question that asks what is it, in this example is a pile of stuff and various connectors.
Unlike going to a hobby store and consulting with a specialty technician we are ordering things online and they are usually not what we want.
We are in an era were supply cannot keep up with technological change. Because yesterday's parts are often obsolete the vendors find bargains and pass them on as the latest and greatest using descriptions that lead to disappointment. Each component can have it's own schematic.
A controller without technical information can end up in smoke, the fan slows down you buy more parts and you have one of each.
There are people who bought a cordless drill that will have fun making holes in something like this.

 

What is not clearly mentioned is if the heating element is powered by a direct connection to the mains, or if it is powered by that same transformer. What is not mentioned at all is the watt rating of that heating element. Clearly this may make a large difference if the heating element consumes many watts.
No matter what, if they are both drawing power from the same mains circuit, and the voltage changes, there is some resistance in the portion of the mains supply that is causing a voltage drop.
The easy way to locate that voltage drop is to allow both to operate until the high resistance section catches fire. NOTE THAT I DO NOT RECOMMEND THIS APPROACH. I only say it is easy. It happens often when somebody connects a 1200 watt heather through a 5 amp extension cord.
So my good advice is to carefully measure the mains voltage at the point where both items are connected. If that voltage drops then there is a problem to be addressed by somebody qualified to service mains wiring.

 

Obviously, you are overloading the transformer when the heater and fan are both turned on high.
Measure the voltage dropping to see it.

Ok, but I didn't connect the heating element to the transformer, but rather to the mains. Means they are both connected to the mains

 

Maybe the value of the rectifier, filter capacitor is too low for the DC to remain at the maximum.

Ok, do you have any idea because it might be useful to me. Thank you

 

You need at least an 18 vac to 20 vac secondary.

Ok, is that the solution to my problem ?

 

You have a heater and its controller connected to a 15V transformer.
Also you are running an up-converter doing 15Vdc to 26Vdc in order to run a 24Vdc brushless fan
And it's controller that is drawing 180 MA.
You noticed the fan speed is opposite of how it should work.
Because of the variety of modules and applications, there are many choices with slightly different wiring.
Can we narrow down the choices?

Sorry, there's a mistake in your statement I didn't connect the heating element to the transformer but rather to the mains. both of them are connected to the mains

 

What is not clearly mentioned is if the heating element is powered by a direct connection to the mains, or if it is powered by that same transformer. What is not mentioned at all is the watt rating of that heating element. Clearly this may make a large difference if the heating element consumes many watts.
No matter what, if they are both drawing power from the same mains circuit, and the voltage changes, there is some resistance in the portion of the mains supply that is causing a voltage drop.
The easy way to locate that voltage drop is to allow both to operate until the high resistance section catches fire. NOTE THAT I DO NOT RECOMMEND THIS APPROACH. I only say it is easy. It happens often when somebody connects a 1200 watt heater through a 5 amp extension cord.
So my best advice is to carefully measure the mains voltage at the point where both items are connected. If that voltage drops then there is a problem to be addressed by somebody qualified to service mains wiring.

The heating element is not connected directly to the main but rather to a circuit that controls it

 

The heating element is not connected directly to the main but rather to a circuit that controls it

Way back in this thread, someone asked for a schematic. It doesn’t have to be professional quality. But it does have to show how your devices are connected. Complex sub-systems, such as the controller can simply be a labeled block.

Draw it on a piece of paper, take a picture and post it here.

This is important to getting the proper help.

 

Measure the mains voltage at the transformer primary to see if the voltage changes as the power to the heater is increased. If you won't provide a schematic can you at least provide a block diagram of the system.

Les.

 

The heating element is not connected directly to the main but rather to a circuit that controls it

If the circuit controlling the hearer element is powered by the mains then the heater power is coming from the mains. It matters not what is in between, unless it is a separate power source.

 

See post #4, you are not going to get 24vdc from a 15v secondary also need at least 5va to 10va.

 

It's working now. The problem was the extension cord. Thank you all for your replies

 

It's working now. The problem was the extension cord. Thank you all for your replies

Pot #13 did rather point in that direction.

 

Pot #13 did rather point in that direction.

Yes.