Dew heater band PS has died after only one month.

[Rusted]

Thanks Julian. Well worth considering. 

 

Thanks again fs,

My wife swears by her B&D [battery] Alligator scissors style chainsaw.
She has a range of saws. Some on long poles and similar, extendable hedge clippers.
I am excused tree trimming because it all too often leads to "an excess" in my wife's opinion.

Point taken on the resettable fuses. I shall aim low. 
LEDs do at least reduce the risk of failing to spot a blown circuit.
This was how I finally noticed my dew band controller was inactive.

I wasted quarter of an hour waiting for dew to clear but it didn't.
The controller was on the other side of the saddle out of sight.
Besides, light pollution is not too much of a problem for solar imaging.
 

[fifeskies]

Yes I wanted to be sure my dew heaters were on so added the LED monitor, cant just trust they are on and end up ruining lots of exposure time.

My controller sits under the owl cage plate so I can see the faint reassuring red glow.

 

🥵 solar isn't something I have tried (yet) , but it suffers just the same from clouds I expect 💭💭💭

[Rusted]

My shiny new Mean Well RS150-12 PS has arrived. It has no instructions and NO mains voltage markings.
Not even an external adjustment switch. Yet it warns against using the wrong mains input voltage.

Would anybody like to guess whether such goods are always 230V in the EU?

My online dealer, RS Europe, doesn't answer such "technical questions" from private customers.

I have searched for this information online but came up blank.

Now I am afraid to connect it to the mains in case I fry it with too high a mains voltage.
Could the absence of such information indicate 230V 50Hz is standard?

Yes, I am well aware of the dangers of exposed mains on the screw terminals and shall house it safely.

 

Edited November 10, 2020 by Rusted

[gilesco]

2 minutes ago, Rusted said:

My shiny new Mean Well RS150-12 PS has arrived. It has no instructions and NO mains voltage markings.
Not even an external adjustment switch. Yet it warns against using the wrong mains input voltage.

Would anybody like to guess whether such goods are always 230V in the EU?

My online dealer, RS Europe, doesn't answer such "technical questions" from private customers.

I have searched for this information online but came up blank.

Now I am afraid to connect it to the mains in case I fry it with too high a mains voltage.
Could the absence of such information indicate 230V 50Hz is standard?

Yes, I am well aware of the dangers of exposed mains on the screw terminals and shall house it safely.

 

http://www.farnell.com/datasheets/2286959.pdf

[fifeskies]

These are usually dual voltage

"88 ~ 132VAC / 176 ~ 264VAC selected by switch 248 ~ 373VDC(Withstand 300VAC surge for 5sec. Without damage)"

there is probably an internal switch to set either nominal 120 or nominal 230

[Rusted]

Thanks but I have read the data sheets in several languages already.

I have read the Mean Well switching PS FAQs. Nothing on mains voltage selection.

Edited November 10, 2020 by Rusted

[Rusted]

1 minute ago, fifeskies said:

These are usually dual voltage

"88 ~ 132VAC / 176 ~ 264VAC selected by switch 248 ~ 373VDC(Withstand 300VAC surge for 5sec. Without damage)"

there is probably an internal switch to set either nominal 120 or nominal 230

Will it make the magic smoke if I connect it without changing this nominal setting?

[gilesco]

Just now, Rusted said:

Will it make the magic smoke if I connect it without changing this nominal setting?

From the schematic, the switch is between the EMI Filter and the Rectifier and Filter.

[fifeskies]

will not survive 230 if set for 120 I suspect

 

see diagram for switch

 

 

[Rusted]

Thank you both. 

I know what the words mean but not what the components look like.

Time for an inward gaze through the casing.

I'll be back.

[fifeskies]

Its possibly a small slide switch on the PCB

though there is a chance its a pin header you lift up and move across

 

[Dr_Ju_ju]

There is also a terminal cover available from Mean Well i.e. https://www.meanwell-web.com/en-gb/cover-for-terminal-blocks-d-id-60-ned-t-75-rd-85-tbc--07  or if you're able you can easily design & print one e.g. 

 

[gilesco]

2 minutes ago, Rusted said:

Thank you both. 

I know what the words mean but not what the components look like.

Time for an inward gaze through the casing.

I'll be back.

Yes, it doesn't look like a normal consumer unit, to be honest, so some investigation will be needed. It seems to indicate that you disconnect a second line to the rectifier to handle ~230V. Put in a second line, and it will double up an input of ~120/130V.

[fifeskies]

[fifeskies]

 

https://electronics.stackexchange.com/questions/183695/rs-150-12-ac-input-switch

 

Edited November 10, 2020 by fifeskies

[Dr_Ju_ju]

I believe it would be the same as a model I just happen to have about my person, i.e.:  which is auto sensing, look at the way the input is shown i.e. 100-240VAC, so no internal switch, but there is a fuse

 

 

[Rusted]

Many thanks for going to such trouble.

I found it just before checking back here.
The Big Red Switch is showing 230V. Phew!

There is a big yellow label on top of the casing pointing straight at it .
I didn't have my reading glasses on.

Thanks again for all the help!

Ever onwards!

[fifeskies]

3 minutes ago, Dr_Ju_ju said:

I believe it would be the same as a model I just happen to have about my person, i.e.:  which is auto sensing, look at the way the input is shown i.e. 100-240VAC, so no internal switch, but there is a fuse

 

 

 

Thats the 200w version.   OP has the next one down , the 150w version.

 

Looks like 200w has autosense but the 150w is manual set

[Rusted]

Thanks to Julian as well.

I think I/we have the problem covered.

Now I just have to avoid electrocuting myself!

That would be ironic after 9 months of self-isolation!

[Rusted]

Just now, fifeskies said:

Thats the 200w version.   OP has the next one down , the 150w version.

Looks like 200w has autosense but the 150w is manual set

Agreed. My perforated case is wrapped around the base and would not come apart easily.
So I used a good light, my strongest [supermarket] reading glasses and a magnifying glass.

[fifeskies]

Supply the PSU via an RCD to be sure you stay safe.

All my mains in my observatory is supplied via a 30mA 2 pole RCD in the small local consumer unit powering my sockets.

[Rusted]

Just now, fifeskies said:

Supply the PSU via an RCD to be sure you stay safe.

All my mains in my observatory is supplied via a 30mA 2 pole RCD in the small local consumer unit powering my sockets.

Good advice except that I'm in Denmark. No earths as standard.

The CU has a RCD but nobody uses [as far as I know] a plug type RCD in the 2 core mains to their lawnmowers, etc.

[fifeskies]

You will be protected at source and all your power should be safe as long as your property meets Danish standards

 

Since the early 1990s earthed sockets have been required in all new electric installations in Denmark. Older sockets need not be earthed, but all sockets, including old installations, must be protected by earth-fault interrupters (HFI or HPFI in Danish) by 1 July 2008.

 

Earth fault interrupters are essentially the same as RCD in that they disconnect inbalance faults caused by a person touching a live wire.

 

 

[Rusted]

7 minutes ago, fifeskies said:

You will be protected at source and all your power should be safe as long as your property meets Danish standards

Since the early 1990s earthed sockets have been required in all new electric installations in Denmark. Older sockets need not be earthed, but all sockets, including old installations, must be protected by earth-fault interrupters (HFI or HPFI in Danish) by 1 July 2008.

Earth fault interrupters are essentially the same as RCD in that they disconnect inbalance faults caused by a person touching a live wire.

Thanks. We had a new socket installed outside our bathroom for a washing machine by qualified electricians.
I asked about earthing and was told it wasn't needed. So a "normal" 2-pin socket was installed.
At the very least a Schuko plug and earthed socket should have been mandatory. [Or so I believe.]

I wanted my British Hifi earthed to kill the loud hum but they weren't interested in installing an earth.
So I bought my own 2m rod and hammered it in outside while they worked elsewhere.
Finally the earth rod was connected to the dedicated spur and I now had the only earthed socket in the entire house.
The hum was gone. The maximum draw on the mains is 10A. Put two things on at once and you blow the main 10A fuse!

My observatory is run on a generously dimensioned, extension cable from a normal, 2-pin socket indoors.
The cable is run through high quality, non-kink, bright yellow, garden hose. I used a long draw wire to avoid needing joints.

I hammered a 2m+ earth rod into the damp soil at the observatory and have earthed my big mounting with a thick cable.
The very high cost of having any electrical work done is a serious hurdle to Danish Standards being observed.

[fifeskies]

I have an electrical engineering background, so apologies for becoming a bit technical.

And don't be too worried about what follows , your installation has clearly been working well without problems for some time.

Its just a "for info" comment.  (and not having seen your installation I am making a few assumptions).

 

 

You have turned your observatory into what is termed a "TT" installation by using the local earth rod if it is connected into the incoming supply.

This now makes your observatory earth point and your source earth point at your consumer unit at a very slight changed potentials.

While in all probability all should be fine with this I would still be tempted to install a local 2 pole RCD/interrupter at the observatory end.

The disconnect time can be affected by relying on the source protection at a far origin when you "TT" your installation.

A local protective device will ensure you get the fast disconnect at 30mA fault you need.

 

 

If just the pier is earthed and not the incoming supply you have an "exported TN-S" type supply and the source protection should probably be adequate,  a local RCD will not cause any problems, but may be superfluous. 

Exported TN-S does have cable resistance limits to function correctly , a long cable that is not of adequate thickness (cross section) will mean circuit protection can fail to operate as expected. In the UK exported TN-S is actively discouraged for this reason.

However with exported TN-S you need to ensure any mains equipment of type 1 , ie with an earth connection , does not come into contact with the "TT" earthed pier as this then reverts the electrical installation to a "TT" type.

 

 

https://uk.rs-online.com/web/p/rcd-plugs/7508450/

https://uk.rs-online.com/web/p/rcds/0490157/

 

 

My own observatory has a TT installation with its own earth rod and I have used a local RCD in the observatory to ensure maximum safety.

 

Note: 

1 Most computer screens running on mains are type 2 (no earth) so dont cause problems when you mount to a pier

2 All the equipment run on 12 v from your supply will be isolated from the mains so should not cause any issues on the earthed pier. However the ground (-V) line on the supply is connected to earth via a capacitor to help avoid it floating too far away from local ground potential and supress ripple noise. So try to avoid the 12v supply touching the pier. 

Edited November 10, 2020 by fifeskies