power Supply Advice

Hardware MikroTik hardware general
1

Hi

I have several RB411AR boards fitted with additional R52h wireless cards.

They are fitted in custom made extruded aluminium cases and work very well.

However, when powered via a 12v AC adaptor the cases exhibit a high frequency vibration which one can notice when lightly touching them. It is hard to describe but the initial reaction is to recoil somewhat. Powering up using the adaptor and a POE injector results in the same.

When powered directly via a 12v battery this does not happen.

I have tried all sorts of supplies, with and without chokes, to no avail.

Can anyone give any guidance as to the best type of power supply for these boards and are there any best practices for installing these boards in a case?

Many thanks

Gary

2

What is preventing you from using either 18v or 24volt power supplies and what is the current rating of the 12v power supply it is DC and not AC @12volts

3

Hi

The power supplies are 240v AC → 12v DC and have ranged in rating from 2 to 5 amps.

I haven’t tried with higher output voltages but shall do.

4

Have you tried earthing the cases ?

5

Nope - but to do so I would need some guidance.

These units are to be used internally (and moved on a regular basis) so I am not sure how one would earth the case. Given that I wish to power the units with an AC/DC adapter, where would I provide an earth from and to?

Thanks

6

Hmm.. Interesting

Are the power supplies grounded? (I.e. three prong)

7

I have tried a mixture of supplies - I have also now tried a 24v supply with the same results.

Most are wall type adaptors with the third prong made of plastic.

I do believe it is earth related as the issue dissapears if I:

a) connect the serial cable or
b) connect a LAN cable or
c) touch the N type RF plug

Thanks

8

If you are unsure on grounding it would be wise to consult an electrical engineer as there may be a bigger issue here like improper power wiring which is dangerous.

If the box is mounted outside for example I would use an earth stake (from an electrical wholesaler) inserted into the soil and wired back to the chassis of your Mikrotik.

Be wary of ground loops if you use POE as that can create another issue entirely.

Again, I think you may need an electrician to check over your power before going further.