Let the fun begin !!! ???

**Clive S** · 12-03-2015

Originally Posted by PAULRO

finally got back to the power supply and got it set up . i'm reading 73 V DC . is this o.k. ? i know that 68 v dc is the magic number . is there a way to reduce it other than reducing the number of windings. i would not be comfortable with stripping out the coil to achieve that.

Its fine at that and are measuring it without a load as well also the mains voltage will fluctuate.
How about a pic. ..Clive

**JAZZCNC** · 12-03-2015

Originally Posted by PAULRO

finally got back to the power supply and got it set up . i'm reading 73 V DC . is this o.k. ? i know that 68 v dc is the magic number . is there a way to reduce it other than reducing the number of windings. i would not be comfortable with stripping out the coil to achieve that.

What drives are you using.? If 80V max then it will be fine but if 75V max then it's a little close for comfort because as Clive says mains does fluctuate. When your reading 73Vdc what is the Mains input reading.?
Also as Clive says you have no load so connect the drives with motors attached and then check.

**PAULRO** · 12-03-2015

I'm waiting for the drives ( EM806) ,bob ( PLC4x-G2) , and motion control( PLCM-E3) card to arrive from Zapp. I just have the 70 V DC supply hooked up . i 'm hoping i'll have the electronics from Zapp tomorrow because i'll have a weekend run at the panel so hopefully the voltage will drop when i hook up the electronics and motors as you say. i 'm reading a steady 230 v ac at the input side. i haven't got the bleed resistor hooked up either and i'm still reading 45 v dc at the cap even though i powered it up for a minute or so yesterday. still, this is progress for me because i never built a supply before , so hats off once again to the heads sharing the knowledge.

**PAULRO** · 13-03-2015

my electronics won't be with me until monday / tuesday . i had an email stating they're in transit , i put some more bits on the back plate i had an old 5vdc power supply plug in type set a side for the motion control card . i couldn't get a din mounted supply locally and i didn't want to wait for ebay so i'll give this a try. i still have to change the fans around on the box i'll tackle that tomorrow . i hope!!!

**JAZZCNC** · 13-03-2015

Can I make a few suggestions.!!

I wouldn't locate the VFD and the PSU next to the BOB and Motion control card and drives. Both these are very noisey devices and they could introduce noise onto the signal wires.
Ideally you want them furthest away from any signal devices like BOB and Drives.

Personally i'd have PSU and VFD at top and Drives/BOB/Control at bottom with Connections/24V psu etc in between with separation.

**PAULRO** · 15-03-2015

I had to put a breaker into my main board to support the extra load for this cnc and i forgot to power down my p.c. so the end result was a p.c. with a blown power supply .
i had a spare one from another m/c but it had different connectors so i spent the morning cutting and pasting.... who needs it ? anyway i changed the panel around and put the noisy bits on top i have to put more fuse holders, terminals etc. in tomorrow.

**PAULRO** · 25-03-2015

i 'm just getting back into the build today and i have the electronics mounted on the back plate. i have a query regarding the fuses for the 70 V DC power supply. i have the fuses on the negative side of the supply , is that o.k. ?

**Clive S** · 25-03-2015

Originally Posted by PAULRO

i 'm just getting back into the build today and i have the electronics mounted on the back plate. i have a query regarding the fuses for the 70 V DC power supply. i have the fuses on the negative side of the supply , is that o.k. ?

Its good practise to put fuses in the +ve side and the mcb for the input to the transformer appears to be 3A I would think you need more like 6A because of the inrush to the coil and rate it to a motor type ..Clive

**PAULRO** · 25-03-2015

cheers Clive , i have a 6A in there , i just for got to update the dwg.! i better change the fuses around .

**PAULRO** · 26-03-2015

O.K. state of play so far is that i have the back panel in the cabinet and i'm doing some electrical dwgs so i can at least give myself a fighting chance to get it right . i have a couple of queries before i go and start lashing in wires though. this is what i think i know from reading the posts , so i just need some nudging .

1......am i correct in saying that i need a separate input for the slave home switch?
2 .... i need a separate input for the rest of the home switches combined in series.
3... because i'm combining both limits and home into a single switch i must keep the e stop on a separate input.
4... i also need an input for feed / hold
5..... and an input for stop.
bring my total of inputs to 5 ( MAX. allowed)

i also have alarm terminals on my drive so i'm curious about how i can get these in to an input. i will post some drawings of my proposed electrics as soon as i'm finished.