extruder fault problem and upgrade to 24v.

Dave Parry · 23 Oct 2020, 12:16

Thanks for reply. I think I will go for a 24v system. I have 3 x 30mm fans on the system so will change them, just looked on amazon and they are cheaper than I thought. Just need to decide on a power supply. There is a big cost jump from 15 to 20 amps, but do you think that 15A at 24v would be ok. will keep the power supply external as I don't think I can fit it under the bed, even though I have doubled the height of the bottom part. Only problem is the heated bed. I ordered a 12/24v version and received a 12v only one. Have raised the issue with the seller so will have to wait for his response.

Veti · 23 Oct 2020, 12:26

@Dave-Parry said in extruder fault problem and upgrade to 24v.:

15A at 24v

it really depends on the power draw of your bed. can you tell us the rating?

also consider buying a high quality power supply from e.g meanwell

Dave Parry · 23 Oct 2020, 14:25

Cant find any info on heater bed power, but measuring resistance when cold gives 1.9 ohm which at 12v gives 6.3 amps which doesnt sound right. Neither of my multimeters go above 10a so their no use. Looking at similar square beds they seem to be about 200w. which would be about 15A

Veti · 23 Oct 2020, 14:41

@Dave-Parry
can you link the heater?

Dave Parry · 23 Oct 2020, 15:14

https://www.amazon.co.uk/gp/product/B089ZYZGQW/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

Veti · 23 Oct 2020, 16:01

@Dave-Parry said in extruder fault problem and upgrade to 24v.:

Looking at similar square beds they seem to be about 200w.

yeah that sound like a good guesstimate

Dave Parry · 23 Oct 2020, 16:51

so say bed = 9 A,
v6 40w = 1.6A
nema 17 Stepper motors = 1.6A x 4, 6.4A
Thats about 17A, so I think I need 20A. does that sound about right?
I know the motors wont draw that much in realitity, but I think 24v 15 A is a bit low.

Veti · 23 Oct 2020, 16:53

@Dave-Parry

see
https://duet3d.dozuki.com/Wiki/Choosing_the_power_supply

you need to calculate the nema differently

Dave Parry · 23 Oct 2020, 17:01

So does that mean 2.8v x 1.68A = 4.5A per motor?

Dave Parry · 23 Oct 2020, 17:16

My Bad, just read again and its 1,68A + 50%= 2.5A x 4 = 10A
So thats 20 A + other bits.
So probably 25A or 30A is going to be the required current.
Thats a lot, no wonder 12v 15A is having problems.

Phaedrux · 23 Oct 2020, 17:34

Definitely consider a meanwell supply from a reputable supplier like digikey or mouser.

Dave Parry · 23 Oct 2020, 18:50

Next problem is a power connector. 25 amps is a lot for a connector to handle.
My present one is a 8 way one, 3 for +, 3 for -, and 2 I think are for power switch.
Not sure what type they are but I think they are molex ones. What type do other machines use?

Phaedrux · 24 Oct 2020, 01:13

@Dave-Parry said in extruder fault problem and upgrade to 24v.:

Next problem is a power connector. 25 amps is a lot for a connector to handle.
My present one is a 8 way one

I'm not sure what you're referring to? Photo?