Help needs for AC Current Control.

[wslim]

I just bought a ceramic heater which is requiring:

Input: 230VAC (50Hz)
Output: 25VAC (Current: 8~10A, controllable), 50% Duty Cycle

I could not find any power supply which can operate for this heater in market.
Is that anyone can help in this matter?

The supplier is just provide the manual as attached within.
I have no idea solving this problem.

 

[BradtheRad]

The manufacturer's instructions just show a box labelled 'controller'. They left it at that, because they know it will not be easy to obtain a power supply that can adjust several hundred watts.

The instructions say you need to raise or lower power gradually.

The easy way to do this is with a variable transformer or autotransformer (Variac). You just turn the dial at the top.
Cost is in the vicinity of $170. You need one for 230V at 10A.

You can also get a fixed step-down transformer, 230 to 25 V. Then add a control circuit of some kind, to adjust power at will.
The control circuit can go either in the primary (high voltage) side, or the secondary side.

If in the primary side then you only need to switch a couple amps, and a triac might be sufficient. However you are dealing with the hazards of high voltage.

If in the secondary side then it is less risk to deal with low voltage. But you'll need heavy-duty components.

 

[wslim]

Would you mind to give me some opinion or where I can purchase of this variable transformer? What kind of specification I needs to show to shopkeeper?

 

[FvM]

The manual isn't clear about the expected control method. In case of doubt, phase angle control can be used. So essentially a 230/25 VAC 250 VA transformer and a dimmer suited for transformer load should work.

 

[BradtheRad]

The variac alone is not foolproof. One could easily dial it past 25V, ruining the heater element.

It is really safer to install a fixed 240 to 25V 10A transformer. Then control the 240V supply with a 2A variac.

Typical variac:

The instructions say to raise or lower power gradually. But it is not convenient to stand around turning a knob slowly.
It would be better to make a regulator circuit that does the same thing automatically, over several minutes. This will require more effort, and it may require a motorized variac.

 

[picgak]

I just bought a ceramic heater which is requiring:

Input: 230VAC (50Hz)
Output: 25VAC (Current: 8~10A, controllable), 50% Duty Cycle

I could not find any power supply which can operate for this heater in market.
Is that anyone can help in this matter?

The supplier is just provide the manual as attached within.
I have no idea solving this problem.

Your ceramic heater mentioned in the manual (caution No 4) is having a low cold resistance so you should not apply 25v directly at start, there should be a soft start in your power supply as well as a current limit.