Turning on Power supplies

D

dannyp

Full time elf
Joined
May 12, 2010
Messages
275
Location
Sydney
I read on another thread that when you turn on the Power supply, there is an inrush which may trip the fuse if there are too many PSUs on the same circuit. My question is how do people sequence the PSU's to turn on at different times to avoid the inrush issue?
 
This year I'm going to try a network 'PDU' (Power Distribution Unit).
It takes a network command and switches the outlets, including the function for an offset delay on the unit.

1693745987744.png

I run Home Automation with Home Assistant, so I find it easy to automate things through my IoT network.
But this is advanced..... Multiple timers like @burnt said is what I did previously and it achieves the same task of delayed switching!
 
Everyones setups are different.
Depending how everything has been setup you can do multiple things to limit inrush current.
1st Step is to research into the PSU's to be used, as you will find a lot of the cheaper up front cost PSU's suffer terrible total Current and to some extent the inrush.
Simplist is to have the PSUs on different switches and power them up manually in groups that limit the total inrush.
You can push PSUs onto different circuits to spread it
You can use timers, or a sequence start system (PLC/Relays/Timers etc) as Burnt has said.
You can have a D curve breaker installed for dedicated points.
 
I would not worry about the inrush issue, unless you experience it.

My answer is based on running a show off multiple circuits with standard residential circuit breakers, or ground fault / RCD breakers... if you have something else maybe you need to do something differently. These breakers expect inrush currents from many kinds of devices... essentially they will allow a brief pulse of current far in excess of the marked current. It would likely take an inrush of 3-10x the marked current to magnetic trip the breaker, depending on its class.

If you have so many PSUs that you have the inrush issue, you probably have so many PSUs that you can't use them all at once at anywhere near capacity. I made this mistake once - I found that a circuit would trip instantly when switched on, but that I could plug it in a little at a time and be OK, a classic sign of inrush issues... Then I counted up the devices on it, and there were 18PSUs (total rated capacity of 6300W) on a 20A (2400W) circuit... so I just split it up.
 
I have a pair of 4ch Cbus relays that connect into the rest of my house lighting. The one driving the PSUs for the pixels have all for outputs run off the same channel, with them set to switch on at 1, 33, 66 and 100%.
I then just have a single command to perform a dimming ramp from 0 to 100% over 4 seconds. This way they are staggered by about 1.3sec each.

The other four channels are used for my P5 tune to, transmitter, and amplifier. These are controlled from FPP, the first two turning on prior to the show, and the amp driven by my Push for Music scripts.
Final channel is currently unused but i am sure I'll find a use for it this year 😂
 
I use timers/relays to have a small 30sec gap when each controller box turns on. There are a bunch of different relays/timers/smart devices you can use to achieve this. I’m using the Shelly 1PM plus devices, just personal preference to how you want to do it.
The little red device is the Shelly relay. I have a total of 9x600w power supplies using a bunch of different non-dedicated circuits that are connected to external power points.
 

Attachments

  • IMG_3303.jpeg
    IMG_3303.jpeg
    1.2 MB · Views: 41
I use Sonoff Wi-Fi smart switches with the eWelink app . I set the timing of the on and off 4/5 years ago and haven't touched them yet , They are much the same as Johnnyboy Shelly's but I place mine at the power outlets.
 
I use Shelly 1 PM switches, and stagger the turn on times to be 1 minute apart. You can also use normal WiFi outlets like the TP Link Kasa (if you can still find them - controllable via a plugin from FPP) or TP Link Tapo (which replaced Kasa I think) or the normal Arlec ones. They run at about $20 to $25 from Bunnings.
 
Johnnyboy said:
I use timers/relays to have a small 30sec gap when each controller box turns on. There are a bunch of different relays/timers/smart devices you can use to achieve this. I’m using the Shelly 1PM plus devices, just personal preference to how you want to do it.
The little red device is the Shelly relay. I have a total of 9x600w power supplies using a bunch of different non-dedicated circuits that are connected to external power points.
Click to expand...
So if I understand this set up correctly, you have the 240 v ac coming into the relay and then from the relay into the ac connections on the PSU? So the power from the PowerPoint is always on but you then program the relay to turn on the PSU at preset times?
 
dpavisic said:
So if I understand this set up correctly, you have the 240 v ac coming into the relay and then from the relay into the ac connections on the PSU? So the power from the PowerPoint is always on but you then program the relay to turn on the PSU at preset times?
Click to expand...
Exactly right. It effectively just an automatic on switch
 
Johnnyboy said:
I use timers/relays to have a small 30sec gap when each controller box turns on. There are a bunch of different relays/timers/smart devices you can use to achieve this. I’m using the Shelly 1PM plus devices, just personal preference to how you want to do it.
The little red device is the Shelly relay. I have a total of 9x600w power supplies using a bunch of different non-dedicated circuits that are connected to external power points.
Click to expand...
I got one of the Shelly 1pm plus relays like you. Could you take a picture of how yours is wired up?
cheers
 
You must log in or register to reply here.
Back
Top