OK, I think I've got a likely candidate. Although I don't know which side is the primary and which is the secondary. One side has large wire 1.25mm and the other has small wire .43mm The large wire wraps approx 110 times and the small wire wraps approx 2400 times. There is no other taps. The outsie dims are 75mm x 75mm x 90mmtall and weighs in at a hefty 10lbs.

Kind of chicken to apply a 110V to this puppy without knowing what the consequnces will be if I hook it up to the wrong side.

 

Hi,

What a monster! The turns ratio should give a reasonable estimate of the output voltage. The lack of mega insulation strongly suggests that it is a step-down rather than -up transformer. That would mean it's likely to have an output of around 5 VAC, and should handle some current.

To keep things to a dull roar, grab an old-fashioned procelain lamp socket, and put it in series with one of the putative input lines. That should be the fastons. Put a 40 watt lamp in the socket, and your pole pig won't blow up if you got the wrong side. It will keep current way down, but let you measure the (almost) correct output voltage. Not much way to tell current, but if it's down around 5 - 6 volts, it's gonna be up there.

If my lights dim, I'll know you left out the lightbulb limiter.

 

Well you nailed it! I measured the o/p voltage at 3-4 volts. I don't know what the current might be for it, but I'm sure it's substantial.

Me, leaning on the side of caution, have decided to go for a Toroidal 30V 20A supply with about 50,000uF capacitance ($114 out of Digi-key)

That should be lots of power to run all 7 motors.

X - 5.0A
Y - 3.4A
Z - 3.4A
U - 3.4A
V - 1.4A
W - 1.4A
A - 1.4A

Total = 19.4A

 

Hi,

Yeah, the current out is probably way up there, but not at a useful voltage. That supply form Digi should do the trick.

Good luck with the L298.

 

Hopefully that will solve the problem.

Thanks so much for your interest and help.

Sid

 

OK, I got a real good power supply which puts out 30V nicely and by the book is rated for 20A. Seems to be working fine.

One problem. When I power up the 5V supply to the the board, the 30V supply suddenly drops to 1.6V! When I unplug the line it measures 30V again and when I power off the 5V, it measures 30V. It seems that when I have 5V power on the board, it drops the motor supply to 1.6V.

Any ideas?

Thanks,
Sid

 

Hi,

That's interesting....

Where are you measuring the voltage? Does the voltage right out of the 30 volt supply go down?

You do have a common point between the 5 volt supply and the 30 volt supply, right? - so there's one common ground in the circuit?

 

Initially I had between the 5V ground and the 30V ground a 4.7uH Choke and a 10uH inductor. Thats all that was connecting the two different grounds. This is when I measured the 1.6V supply where it should have been 30V.

I read your post this morning and added a direct jumper between the grounds and then tried it again and now I measure 0V! nothing.

I unplug the 5V supply and measure the motor voltage and it's 0V.

Sid

 

Disregard that. I hooked the jumper up to the wrong post.

I've corrected it, but it still only measures 1.6V.

I was suspecting the L297's, but I should still be getting 30V at the plug where the power supply connects.

 

Hi,

Yes, your power supplies should share a common ground without affecting the output of either. Has to be something strange about that.

Anything that could load the 30 volt supply down that far should be visible as the origin of all that smoke.

 

Hi,

Yes, your power supplies should share a common ground without affecting the output of either. Has to be something strange about that.

Anything that could load the 30 volt supply down that far should be visible as the origin of all that smoke.

 

Hai,
I am using L298 for controlling magnetic latch. This takes current upto 2A.
I decide to parallel its channel.
From L298 datasheet, page7. For high current ratings L298 outputs can be paralleled.channel 1 with 4 and 2 with 3.
Can you advise the significance of it.
What happen if i parallel 1 with 2 and 3 with 4?
When i use the alternate bridges parallel, i can't control the enable other wise the other channel will get uncontrolled. So i have to leave other channels unused.
waiting for some valuable reply.
vigneshwaran.

 

Hi,
Sorry I can be of no help in that respect. I have not tried the L298's in any other capacity other than stepper motor control. The channels are paralleled as per the datasheets and work fine. As for what you wish to do with them, I'm afraid I have no input.
Good luck with them, and if you get them working, post your circiut dia here as I would be interested in seeing the application.
Cheers

Hai,
I am using L298 for controlling magnetic latch. This takes current upto 2A.
I decide to parallel its channel.
From L298 datasheet, page7. For high current ratings L298 outputs can be paralleled.channel 1 with 4 and 2 with 3.
Can you advise the significance of it.
What happen if i parallel 1 with 2 and 3 with 4?
When i use the alternate bridges parallel, i can't control the enable other wise the other channel will get uncontrolled. So i have to leave other channels unused.
waiting for some valuable reply.
vigneshwaran.