Over heating Power box switch.

For items about gas turbine, IC and Electric powered jets, engines and systems

Moderators: jamie cuff, Dick Spreadbury

stevewhite
Posts: 9
Joined: Mon Jul 14, 2014 12:10 pm

Over heating Power box switch.

Postby stevewhite » Fri Mar 25, 2016 8:29 pm

Hi has any one had a problem with a Powerbox switch overheating and cutting off the radio in the model, seems to be happening to my L39.
Was setting up control throws up at the field, had the radio on for aprox 20 mins when the model just went dead, the switch was red hot.
Let it cool down and the radio came back on! Left it on for another 15 mins and the radio went dead again, the switch was red hot again, let it cool down and the radio came back on.
Checked the amp output which was 0.8 to 0.9 with the servos at rest, is this about right?
Any input would be welcome.
Cheers Steve

Dave Wilshere
Posts: 452
Joined: Sat Nov 23, 2013 6:25 pm

Re: Over heating Power box switch.

Postby Dave Wilshere » Sat Mar 26, 2016 12:32 pm

Which switch?

The current draw is amp limited. Servos all vary on current draw, some makes draw more, ball links that are tight draw more.
Flaps that come hard up against stops are the biggest cause.

So, model size? number of servos/electronic switches and servo type.

A Sensor switch at 5A you should be able to hold your finger on the blue heat sink, just at the limit of pain. Any hotter its pulling more than 5A

Dave

stevewhite
Posts: 9
Joined: Mon Jul 14, 2014 12:10 pm

Re: Over heating Power box switch.

Postby stevewhite » Sat Mar 26, 2016 3:55 pm

Thanks Dave

Just bought an Amp tester to try to find out if any of the servos are drawing high current at idle.
Can you tell me if the switch, its a Power box sensor switch would shut off power to the receiver if it overheats, as this is the most concerning thing and if its not the switch i need to look for another course.
I will have to have a look at the servos as i didnt build the model myselfe, the ones i have seen are Hitec digital.
Its a Jet Ledgend L39
What sort of Amp draw would you expect from the switch with everything unloaded.
Thanks for your help on this as i am new to jets and finding it a steep learning curve.
Steve.

Dave Wilshere
Posts: 452
Joined: Sat Nov 23, 2013 6:25 pm

Re: Over heating Power box switch.

Postby Dave Wilshere » Sat Mar 26, 2016 5:32 pm

Steve

Depends whether its an actual Powerbox Sensor switch or the Hobbyking copy...which is not!
What colour are the wires?
Can you post a picture?
Hitec digitals do draw more current than say JR, but they are normally fine. Digitals hum as they constantly centre, I guess an L-39 with 8 servos and 2-3 valves can sit around an amp with gravity acting.

Dave

stevewhite
Posts: 9
Joined: Mon Jul 14, 2014 12:10 pm

Re: Over heating Power box switch.

Postby stevewhite » Sat Mar 26, 2016 9:03 pm

Hi Dave.
Thanks for the quick reply.
The switch has a Powerbox sticker and logo on the back.and a number SN150616, it also has the blue heatsrink certainly looks correct against the pictures of one on there site.
It has blue and red wires on all four connections.

We tested it at the field and with everything at idle the tester showed a reading fluctuating between 0.7 and 0.9 of an amp. so that seems to suggest no high loading from the servos.
Yet it became very hot after about 15mins without moving any of the servos and the at about 20mins the switch and radio in the model just shut down almost like it lost bind.
But after 10mins it was quite cool and everything came back on!
Did exactly the same thing when i tried it again
Were all a bit puzzeled at the moment.
Steve

Dave Wilshere
Posts: 452
Joined: Sat Nov 23, 2013 6:25 pm

Re: Over heating Power box switch.

Postby Dave Wilshere » Sat Mar 26, 2016 9:49 pm

Then there is a fault with it. If its getting hot doing nothing and its really only drawing 0.9A it should hardly get warm.

Send it back to PB and get them to check it.

PowerBox Systems GmbH
Ludwig-Auer-Straße 5
D-86609
Donauwörth
Germany

stevewhite
Posts: 9
Joined: Mon Jul 14, 2014 12:10 pm

Re: Over heating Power box switch.

Postby stevewhite » Sun Mar 27, 2016 10:28 am

Thanks Dave.
Will send it back to see if it is faulty.
Can you tell me if the switch would shut off if it overheats, cause if it dos thats a real safety issue, and thats what seems to be happening.
Steve.

Dave Wilshere
Posts: 452
Joined: Sat Nov 23, 2013 6:25 pm

Re: Over heating Power box switch.

Postby Dave Wilshere » Sun Mar 27, 2016 12:54 pm

I've never seen it happen, that's why I say there is a fault. The fact it gets so hot there is a fault somewhere. I had a Sensor switch on a 3-D Universe with 2 way vector and gyros and with the servos constantly moving plus the flight controls the heat sink got too hot to touch, but it kept working.
Since you don't know the history of this switch it needs to be checked.

Dave

stevewhite
Posts: 9
Joined: Mon Jul 14, 2014 12:10 pm

Re: Over heating Power box switch.

Postby stevewhite » Sun Mar 27, 2016 7:59 pm

Ok Dave thanks


Return to “Jets”

Who is online

Users browsing this forum: No registered users and 1 guest