Electromagnetic uncoupling

[KevWright]

I'm experimenting with B & B autocouplings, using their own electromagnets. The instructions say to use 6-12v AC or DC, so I'm using a 9v battery, and push-to-make switches.

 

I'm finding that while the coupling loop flips up as intended when a wagon is uncoupled, it's not working when it is coupled. It seems as if there is not enough force to lift the delay latch on the other coupling.

 

The top of the magnet is at baseboard height, about 4mm below the rail tops. Do I need to raise it higher, or maybe supply a higher voltage?

 

Any advice gratefully received! 

[smokebox]

Exactly what battery are you using?  A pp3 battery will probably not have enough "oomph" due to its small capacity and Internal resistance.

[KevWright]

8 minutes ago, smokebox said:

Exactly what battery are you using?  A pp3 battery will probably not have enough "oomph" due to its small capacity and Internal resistance.

That's exactly what I'm using. I was trying to avoid installing a mains connection as my locos are radio controlled so I don't really need one. 

[smokebox]

You could try a bigger battery such as a pp9.

[Izzy]

With these couplings, an etched version of the similar DG type, I have found the wagons must be buffered up against one another otherwise the loop gets caught on the hook and won’t rise. The latch must of course also rise up easily.

 

Bob

[KevWright]

1 hour ago, smokebox said:

You could try a bigger battery such as a pp9.

Thanks for the suggestion. I hadn't realised you could still buy these.

[melmerby]

Or to save on disposable batteries how about a holder for 6 (7.2v) or even 8 (9.6v) AA cells and use rechargeable NiMh batteries?

Higher initial outlay but might be more economical in the long run.

[KingEdwardII]

2 hours ago, KevWright said:

I hadn't realised you could still buy these.

Alternatively take a peek at our RC Airplane brethren and check out the 11.1V LiPo rechargeables ("3S") that they use, which seem to start at around £10 a piece.

 

Yours, Mike.

[Nigelcliffe]

As Keith suggests, or a small 12v battery, such as those for house alarms or smaller motorbikes.    Will require a suitable 12v charger when "back at base".  

 

I'm not familiar with the electromagnet supplied from B&B.   However, current demand (and thus battery type) varies a lot with different electromagnets: the "PK" type often sold for DG couplings is particularly current hungry and in-efficient.   The SEEP type requires considerably less current (but still about 0.5A) for about the same effective pull.

 

A completely different approach would be movable permanent magnets - a rare earth cylindrical magnet on a stick/lever under the track which can be moved into or out of position.  Manually operated requires no power !