curcuit problem

[jimmyplumb]

Hi Guy's
I need some help with this circuit as it does not work. The motor should turn slowly the light should come on & the cooling fan should run but nothing is working. I have been struggling with this project for week's now as I have posted it before as Synchronous motor.
Any help would be very welcome indeed

Jim

[rievax_60]

Re: curcuit problem

One of the bridge diodes has been placed directly across the AC supply, clamping one half cycle.
And another one is across the DC rail doing nothing.

[domas]

Re: curcuit problem

[jimmyplumb]

Re: curcuit problem

My Mistake guy's posted wrong layout that was one I made earlier I have got the proper one here.& Many thanks' for your replies


Jim

[selldoor]

Re: curcuit problem

Have you tried just the motor on the ac from the transformer - maybe you did it a nasty with the DC.
Is the bulb one that can be used on AC or DC or is it just a DC Bulb?
Does the fan work when connected to your DC adapter?

[jimmyplumb]

Re: curcuit problem

Another mistake above

[T30M31]

Re: curcuit problem

Can you provide voltage measurements, type of light, and power requirements for the fan and the synchronous motor?

DC voltage across capacitor?
AC voltage across capacitor?

AC voltage across motor or light?

DC voltage across fan?

[jimmyplumb]

Re: curcuit problem

The motor runs of ac adaptor the light does not which should make it dc the fan is dc if im not mistaken there is the problem on the light????

[selldoor]

Re: curcuit problem

Pinching Domas' picture would this work?


EDIT Possibly - 1 think early led bulbs were all dc recent ones are AC/DC
I dont know if any AC only ones were made

[jimmyplumb]

Re: curcuit problem

The fan& the light both run on DC The Motor runs on AC , Have tried all three with there relevant adapters and they all work.

[selldoor]

Re: curcuit problem

OK so it should work

Just build as per Domas and check that you have DC voltage where he has + and - connect the motor across the ac fan and light across the
DC.. Then add in the cap and thermal cutout.

[jimmyplumb]

Re: curcuit problem

Tried it as this but does not work I have left the capacitor in as it was there at the beginning of the project. This is how it made up now

[selldoor]

Re: curcuit problem

Test voltages as previous poster suggested? list them here.
Test the Diodes?

EDIT
Further thought - I am not sure a 300ma adapter will hack it?
its only 3.6 watts by my reasoning

[jimmyplumb]

Re: curcuit problem

I am only getting 2.63v AC after the jack there is something on the circuit that is not right All diodes have been tested as well as the capacitors & all are good
The motor is only 1-2w

[T30M31]

Re: curcuit problem

You are probably overloading the 300 mA adapter. You should remove the light, fan, and motor then check the voltage. If the voltage is correct then add the devices back one at a time and check the voltage after each one. Also check to see if each device will work correctly without the other 2 connected.

You should sum the power requirements for all three devices and use that to determine what size AC adapter is needed.

[jimmyplumb]

Re: curcuit problem

I disconnected the light & the motor started turning but the fan did not. So I disconnected the motor & the fan still does not run so there in a fault some where with the DC layout???

[selldoor]

Re: curcuit problem

what voltage if any on DC?
does one of the diodes feel hotter than the others?

[budm]

Re: curcuit problem

OK, lets get the info as to how much current each load requires to run:
Lamp = xxxx A
Fan = xxxx A
AC motor = 12V @ 1~2W (~167mA)? for sure, what is on the label?
300ACmA AC transformer with bridge rectifier can only supply 180mA of DC, you will need to calculate the cap size depends on the AC ripple that the load can tolerate.
Right now that transformer can not handle the loads.
Get a 1A transformer so you will have head room and the transformer will run cooler. Also verify your wiring for sure it matches your drawing, seems to have so many corrections from the beginning on this thread and the other thread.

[jimmyplumb]

Re: curcuit problem

Okay now I have disconnected the capacitor & now I get 12vAC & 12 DC At last . I will reconnect everything back tomorrow & repost with the results So thanks a lot guys for all your valuable help it has been very much appreciated

Ps I will also get a better AC adapter


Jim

[budm]

Re: curcuit problem

The 470 uf cap? without cap you will have 120Hz pulsing DC, with the cap in place the voltage on the cap should be around 17VDC, the cap should be 25V rating.
Correct polarity of the cap connected to the circuit?