[PSUBS-MAILIST] MK-101 Connectors

Mon Jul 28 19:46:33 EDT 2014

Cliff,
I made my own 10 pin penetrator and tested it to 1,500 feet in my window test chamber.
It was quite simple, used threaded rod and just bolt the wires on.
Hank 

On Monday, July 28, 2014 4:50:32 PM, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Alan, I am leaning towards using the Subconn BHB2M bulkhead fitting for my MK-101's even with the 25A limitation noted by vendor if we confirm 25A is the limit for both pins.

My argument is that this is a general purpose wet matable bulkhead connector.  Vendor has to protect itself from generally ignorant population that do stupid things.  As such, I am sure they have conducted many worst case tests including 150-200% fully loaded of this 25A limit with the conductor in the air as apposed to submerged for days on end.  

In my case, I plan on using the motor controller that MK supplies for 36V systems and the MK resettable circuit breaker they recommend for the 101 lower units.  MK recommends in the paperwork that comes with the lower unit not to run in the air for more than 2 minutes. The MK motor controller is very nice.  It works off a 0-5VDC potentiometer with a large deadband around 2.5V.  This motor controller has a soft start built in so full on at 0 or 5 vdc causes the motor to ramp up over about 2 seconds or so.  Like wise full reversal of potentiometer causes the motor to ramp down then ramp up.  This soft start capability is designed to limit high initial current load that it would see if you just connect motor directly to battery bank.  Also these controllers are potted.

The second point that makes the BHB2M work for this application is that it is installed on the thruster so that if the thruster is submerged, and if a prop is installed, ambient water is cooling both the motor and the connector.  Also our duty cycle is light.

Could you fail this connector by overheating. Yes, don't use circuit protection, don't use motor controllers with a soft start, run the motor in air for long periods of time.  

As long as you use a bit of common sense, this connector which has 10 AWG pins which is the wire size recommended by the MK for their 101 lower unit, it should work just fine.

If someone can identify the same basic bulkhead connector with say 8 AWG pins that does not cost $2000 per connector, we of course should look at this but I for one am comfortable that for my application this will work IF the cost is reasonable.

Cliff

 From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
Sent: Monday, July 28, 2014 4:13 PM
Subject: Re: [PSUBS-MAILIST] MK-101 Connectors

Cliff, 
you had to go all the way over there, what a long haul.
   I am quoting this from advice I had years ago & I think it was from one of their reps.
From what I remember, it was the combined heat from the 2 wires in the connector 
that was the determining factor.
I will send them an email & post the results.
Alan

 From: Clifford Redus via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
Sent: Monday, July 28, 2014 7:48 PM
Subject: Re: [PSUBS-MAILIST] MK-101 Connectors

We need some clarification  on this.  I am reading this as this connector will handle 25 amps per pin so with a FS 2 we are probably good.

I have had no time to look at this as in Perth on business.

Cliff

On Jul 28, 2014, at 3:08 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Hi Cliff,
>as I understand it the connector amp rating is 25 amps for the 2 pin unit.
>That means 12.5 amps per pin, which is about 1/4 of what you want.
>Cheers Alan
>
> 
> From: Clifford Redus via Personal_Submersibles <personal_submersibles at psubs.org>
>To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>Sent: Monday, July 28, 2014 6:51 PM
>Subject: Re: [PSUBS-MAILIST] MK-101 Connectors
>  
>
>
>I think there is a big factor of safety.  You get the same issue when you look at agency's specs on how much current a 10awg wire can handle.  Having said that MK sells there lower units with 10 awg wire.  US coast guard would have 6 awg for this current.
>
>
>This needs to be looked at but my guess is that this will handle it.
>
>
>
>Cliff
>
>
>
>
>On Jul 28, 2014, at 12:48 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
>Cliff,
>>what about the max contact amp ratings on those connnectors?
>>I thought you said you needed something that could take 46 amps.
>>Alan
>>
>> 
>> From: Clifford Redus via Personal_Submersibles <personal_submersibles at psubs.org>
>>To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>>Sent: Monday, July 28, 2014 4:20 PM
>>Subject: Re: [PSUBS-MAILIST] MK-101 Connectors
>>  
>>
>>
>>Jon, a BHB2M to me looks about right.  10AWG pins to match the 10AWG for the MK-101.
>>
>>
>>
>>
>>The port on the MK-101 is 1-1/8 x 18    So it would be easy to machine an adaptor to accept this 5/8-18 male BH fitting.
>>
>>
>>Can you get a price on these with the Psub discount?
>>
>>
>>There probably enough space to drill a 1/16 hole in this machined part and connect a 1/4" Swagelok fitting perpendicular to the axis to connect an air compensation connection if you did not want to drill and tap into body of MK-101.
>>
>>
>>
>>
>>
>>
>>Cliff
>>
>>
>>
>>Cliff Redus
>>
>>
>>
>>
>>On Jul 28, 2014, at 11:06 AM, Jon
 Wallace via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>
>>
>>
>>Agreed, but we should take advantage of our SUBCONN discount if we
      can.  What about this one...
>>http://www.subconn.com/connectors/power-series/power-series-battery-2-contacts
>>
>>Jon
>>
>>
>>
>>On 7/27/2014 6:00 PM, Clifford Redus via Personal_Submersibles
      wrote:
>> 
>>Since so many of us are using or planning on using MK-101s either air or oil compensated, it would be nice if we could move towards a standard connector.  These thrusters are 36v with max current of 46 amps.  The lower unit comes with two 10 AWG wires. 
>>
>> 
>>It would be nice if the connector was a male bulk head connector with two power pins and one alignment pin.   
>>
>> 
>>Could go with an off the shelf connector like an impulse HDBH-2-MP but these are expensive as rated for depth.  In our case since we are pressure compensating this is overkill.  
>>
>> 
>>For those of you that have MK-101 or MK-80 thrusters, what type of connectors are you using? 
>>
>> 
>>Like Vance, I am planning to have a spare that could be swapped out in the field. 
>>
>> 
>>Cliff 
>>
>>
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