Using dual output power supply in parallel

Question

I have a Tenma 72-10495 72-10495 power supply with two outputs. Each output can deliver 5A current, but I want to use both in parallel to deliver up to 10A. How can I hook up my load to the two outputs to work in parallel? What settings do I have to configure to be in parallel operation?

xueyin.agerris · Accepted Answer

Thank you for all responses so far! To Michael/Sean: yes I was hesitant to hook up my load because the provided documentation doesn't indicate how this particular model is meant to be used in series/parallel operation.

I got in contact with technical support at Element 14 and they sent me these photos in an email:

It's a shame this documentation is so difficult to find. I tried searching the heading in the top right corner, but unfortunately, I still don't know where these pages came from.

Regardless, it is here if others so seek out this information!

michaelkellett · Answer

You may have to do some experimenting ! The manual (which I found on the CPC website) makes no reference to it but there is an indication on the front panel that series or parallel operation is possible. Assuming the second function of the SER/IDEP and PARA/INDEP buttons is like the BEEP button: remove all connections Press SER/INDEP untill the SER led ligts - I guess it will now be in series mode but I don't know if you need to make the serial connection yourself. Connect a meter across the right hand set of terminals and adjust the voltage and see how it changes, do the same for the other set of terminals. Now you know if it does the connection internally and what the meters read. On some instruments the two supplies will track and one meter will read the full voltage, on others you need to do your own addition. You could also ask Farnell/Element 14 why they can't make the effort to supply decent operating instructions with their own brand stuff !! Good luck. MK

rscasny · Answer

I'll agree that the Tenma product manuals aren't as descriptive perhaps they could be. Roadtesting them is a good possibility. I will talk to the product manager to try to get some help. Randall

baldengineer · Answer

xueyin.agerris wrote: For parallel operation, would you say I would have to connect +ve to +ve and -ve to -ve across the two outputs? Well, this question is usually answered by the manual. In other supplies that have a serial/parallel button, you typically use the positive from CH1 and the negative from CH2. A clue would be if you hear relays clicking when you enable/disable those modes. Another way to tell would be to measure the voltage at the terminals to see what pairs are active.

xueyin.agerris · Answer

You guys are right. The model only has one channel on the right hand side, and only two in total. There is definitely a lot of mismatching information happening here.

Yep, I did try it in parallel operation. I hooked up my load to how the picture indicates (and not the text), i.e. across the right output channel only. I didn't need to hook anything up to the left channel. I only needed to set the voltage/current limits on one channel, and the settings were mirrored in the left output indicators. I measured the output current and it was the full current I was expecting.

When I turn on the output however, the screens on each output unit indicate half the current draw. So if I was drawing 12A in total, each output screen would show 6A. The current actually being outputted is still 12A though.

In short, I had no problems hooking the power supply up to how the pictures (not the text) indicate for parallel operation. I have not yet tried series operation.

Jan Cumps · Answer

Text vs drawing in the manual aren't aligned:

michaelkellett · Answer

I'm very concerned that this wiring advice is not correct for this power supply ! It is how you would connect two isolated supplies but if this model was intended to work like that it might not need the external connections. It has two buttons and indicator lights for // or serial operation - on some supplies the metering is correctly connected for these modes, on others you have to do your own addition of current or voltages. On some supplies the special modes cause the supplies to track voltages, on other not. The manual does not mention these modes. Can you post the actual link so we can see where the information came from. MK

colporteur · Answer

Your concern has some merit. The physical configuration wouldn't be my first choice. That being said, it is not a fry the circuit configuration for a dual power supply. As I indicated in my post the configurations may be supported programmatic through the powers supply menu. The description by xueyin.agerris "I would have to connect +ve to +ve and -ve to -ve across the two outputs?" caused me concern. I felt a visual of what would be a correct configuration was better than a verbal. To be honest I'm not even sure if the pictorial is the correct model. The link provided in postings didn't source for me. So I used a Google search that returned a picture.

Using dual output power supply in parallel

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