Author Topic: Advice needed new TTI power supply  (Read 940 times)

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Offline arcticfish

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Advice needed new TTI power supply
« on: December 22, 2018, 06:50:22 am »
Hi Guys,

Wonder do you have experience with TTI power supply particulary EX354RD. I bought one few days ago, and testing out the readings just now. I find that after I press the small off button on left side supply, set the current limit knob to 0, the LED on top will turn red. If I set the current limit knob to about 0.008A, the LED will be off. Anyone know is this a defect? Will the problem degrade over time? The right side of the supply doesn't have this issue, I assume this is good.

Thanks for the advice in advance.
« Last Edit: December 22, 2018, 06:51:55 am by arcticfish »

Offline PTR_1275

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Re: Advice needed new TTI power supply
« Reply #1 on: December 22, 2018, 07:29:22 am »
I’ll start by saying I haven’t seen inside these generation of TTI power supplies.

From memory the old ones used to use a double pole switch that would turn off the output and also give a signal to the micro that it needs to display set current not actual current.

The circuit behind the switch was still running.

There might be a bit of leakage that means when the current limit is set to lower than 8mA it can’t maintain the set voltage and will enter current limit mode.

For example, I set my dp832 to 1mA 13v and the voltage drops to 0. 3mA is just maintaining ~6v and 4mA is slowly increasing the voltage.

Power supplies like this will behave a bit odd when they are at the extreme lower end and as such I wouldn’t be overly concerned about it.

I’ve used the older PL330 supplies for 15 years, plus I have a new PLH120 which is an awesome bit of kit.

Offline Towger

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Re: Advice needed new TTI power supply
« Reply #2 on: December 22, 2018, 07:38:33 am »
The older models go into current limiting mode if you crank the current limit down to zero.   If the design is the same it is probably adjustable with one of the internal trimmers. Bit I would leave it well alone.

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