Skipjack SAS motor RFI caps

[roedj]

David,

Attached is a pic of the power cable end of the motor supplied with the 3.5" SAS for the Skipjack. I don't see any RFI caps installed. Are they internal to the motor case? If not, I would think I should install them. Please advise.



Dan

[He Who Shall Not Be Named]

Recently Mike was able to negotiate a deal with the supplier of our 555 and 380 sized motors to provide them with internal spark-suppression capacitors. And that's the case with your 3.5 motor, Dan. You're fine -- that motor is spark suppressed. You can tell by the small gauge wires that come out of the motor back-plate and are wound around the motor terminals.

Mike is always on the hunt for new product and enhancements that will find utility in our hobby. As Mike buys in quantity he has a lot of clout with the vendors we deal with -- not the case with our competitors who make small purchases.

An example: Mike was shopping at a big Chinese vendor and to please Mike they sent a box full of product samples. Some of the small pump-motors in that box caught my fancy, and the LPB-SAS ballast sub-system was born. That would never have happened if Caswell did not have the full, undivided attention of our vendors.

David

[roedj]

David,

Thanks for your response. I always believed that Caswell/You wouldn't offer a motor that wasn't somehow RFI suppressed.

I must admit, though, that I do have some reservations about routing an unshielded antenna lead along side a motor, RFI suppressed or not. In my multi-year experience of operating radio communication gear in an RFI rich environment (think cars and trucks) I would go out of my way to keep the antenna lead (always shielded coaxial cable) as far away from any RFI generator (thing spark plugs and on-board computers) as possible. Even then, I would ground the shield to the engine block in multiple points.The fact that it apparently works in the confined, RFI messy quarters of any WTC is more a tribute to sound receiver design, RFI suppression through judicious use of RF by-pass capacitors and/or plain dumb luck.

My two pfennigs worth,

Dan

[He Who Shall Not Be Named]

I share your trepidation here, Dan. My hand was forced -- I could not find any other way to get the receiver antenna length to the outside antenna length. However, it works. Never had to run coax between receiver and antenna lug. Amazing still to think that we can get away with this.

David

[roedj]

Just to be totally anal retentive about this, I will run the antenna lead to the outside either:

1) By means of a piece of 1/16" rod (push rod) routed through the waterproof seal nearest the safety float valve with a means to attach wire to both ends and appropriately sealed with RTV, OR

2) By simply attaching the antenna lead to both sides of one of the SAS brass nipples on the back end plate by soldering on some sort of spade lug to both sides of the nipple and sealing with RTV on the outside.

Either way, the antenna lead won't run by the motor at all. I'll be careful to provide strain relief whichever way I go.

Dan

[He Who Shall Not Be Named]

Dan,

I like that! I never considered those two possibilities. I'll investigate the pushrod option. Good, sound, practical, innovative engineering at work here. Thanks.

David