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Bench top power supply problem

Bench top power supply problem

(OP)
I received my 60V 5A bench top power supply through the post today, but how it behaves is really different in comparison to other ones I'm so used to.

For example, if I ever wanted a 12V output, I would get a 12V output. With this one, however, I have no control over the voltage what so ever.

I can only adjust the voltage when it's unloaded. When I connect it to a device, the voltage will plummet and stay fixed. I can only adjust the current.

I wanted it for my motor builds, but if I have no control over the voltage it's useless.

Any suggestions?

RE: Bench top power supply problem

If it has sense terminals, they must be connected to the related outputs, by either a resistor or a short.

More likely, it also has foldback current limiting, and either the devices you are connecting draw too much current for it to supply, or you need to crank up the current limit setting a bit to feed them.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: Bench top power supply problem

There ain't no technical data in the page you referenced.
Actually, there is a little, but not a lot.
Didn't you get a user manual?

Never mind.  It's a 'lab' supply, which means that the foldback is very fast.  That means that it won't start, e.g., a 12V/5A motor, though it could keep one running if the motor was already at rated speed when you connected it.

I.e., the supply will deliver up to 5 amps, with the current control dialed to the max.  If your load attempts to draw more than 5A, the supply will shut down almost instantly, to protect your load and itself.

What are you trying to drive with it?  Voltage?  Rated current?  Starting current?
 

Mike Halloran
Pembroke Pines, FL, USA

RE: Bench top power supply problem

(OP)
There is a manual, but unfortunately it's all in Chinese.

It's for my motor project which hasn't been built yet. I wanted to drive it upto speed with the 60V as well as have some speed regulation.

So basically, this isn't going to work for motor projects?

RE: Bench top power supply problem

For small motors, yes.  You haven't told us how big yours is, or will be, in terms of current or power.

My first encounter with 'lab' supplies, many years ago, involved a 12VDC linear actuator that had a nominal current rating around 10 or 20 amps.  It ran great from a car battery with a contactor to start it.  

My incoming QC department reported the actuator as 'dead' because their lab supply couldn't deliver the 275A or so that the motor needed for a millisecond or two to get started.  The supply turned itself off so quickly that the motor didn't even twitch.

So, go get 5 old car batteries.
 

Mike Halloran
Pembroke Pines, FL, USA

RE: Bench top power supply problem

Similar looking supplies from China are rated 30V 3A.

Just because it states that it is 60V 5A does not mean it will do both 60V and 5A. It might do 5A at 12V, and only 1A at 60V.

RE: Bench top power supply problem

(OP)
My supply is a constant current source. I didn't no they came in so many different 'flavours'.

BK Precision (expensive!) have a nice document to read on their power supplies. I need a 'Battery Eliminator,' constant voltage source or a constant voltage/constant current source not a fail safe 'lab' supply.

 

RE: Bench top power supply problem

I think you just have the current limit set too low.

RE: Bench top power supply problem

Correct its just in "constant current" mode instead of "constant voltage" mode.
The LED near the current knobs should be illuminated now.. You want to get the other light to turn on..

Typically you just turn the power supply on (without any leads/loads hooked to it) and then turn the current knob all the way up. The voltage light should then illuminate and you are in constant voltage mode and should be good to go.

And yes as comcokid said pay attention to the wattage rating.. Many times they state 60V 5A.. But then state like 150W max or something like that.. So you can do 30V@5A (150W) but 60V@5A (300W) will be over its rated wattage limit.  

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