Relay/Contactor Power

[Myforwik]

I have a 24Vdv contactor thats only 6W to hold, but 200W average to
close, with a close time of about 30mS.

What power supply would be suitable?

I find that most 240VAC->24VDC swithmode din supplies mention
absolutely nothing about rush currents they can sustain nor for how
long. Some of them give fast blow fuse ratings if you're lucky.

Usually what would you expect a switchmode supply to be able to burst
and for how long?

 

[Phil Allison]

"Myforwik"

I have a 24Vdv contactor thats only 6W to hold, but 200W average to
close, with a close time of about 30mS.

What power supply would be suitable?

** Errr - one rated at 8 amps ?

I find that most 240VAC->24VDC swithmode din supplies mention
absolutely nothing about rush currents they can sustain nor for how
long. Some of them give fast blow fuse ratings if you're lucky.

Usually what would you expect a switchmode supply to be able to burst
and for how long?

** You can only rely on the rated figure.

Near instant current limiting comes into action above that.



.... Phil

 

[Bruce Varley]

"Myforwik" <myforwik@gmail.com> wrote in message
news:602ac7cd-48e4-482f-9f96-04ac81062842@f20g2000prn.googlegroups.com...

I have a 24Vdv contactor thats only 6W to hold, but 200W average to
close, with a close time of about 30mS.

What power supply would be suitable?

I find that most 240VAC->24VDC swithmode din supplies mention
absolutely nothing about rush currents they can sustain nor for how
long. Some of them give fast blow fuse ratings if you're lucky.

Usually what would you expect a switchmode supply to be able to burst
and for how long?

Have you considered using a large capacitor to provide the inrush current?
That way the PSU only has to deliver the holding current. I do this with
solenoids, it works fine.