Monday, May 3, 2010

Re: [Electric Boats] controllor for mars brushless 48v

 

The first Sevcon PMAC I had (bought Summer 07) would not go into reverse until it sensed the prop had stopped turning forward.  In my slippery launch this could take up to 15 seconds coasting down from full speed.  Could be pretty scary waiting for the 'brakes' to kick in!  Others reported this same issue.
 
Sevcon modified the firmware to correct this.  It will now go into reverse immediately, even if the motor is still turning the other direction.  This required returning the controller to Sevcon.
 
These products are designed with land vehicles in mind which have brakes so not having reverse available until the vehicle is stopped is actually a safety feature. On boats, no so much.
 
If the delay is bothersome you might be able to rig a simple brake on the propshaft to stop the free wheel action.  Seems unlikely the Chinese would redo the firmware for you. 
 
 
----- Original Message -----
Sent: Sunday, May 02, 2010 1:22 PM
Subject: Re: [Electric Boats] controllor for mars brushless 48v

 

Denny,
 
I experience a lag when going from forward to reverse in my electric powerboat running my 5KW Golden brushless DC motor and Controller.  Can you explain to me why?  You seem to know about this as you mentioned about the Sevcon Controller.
 
John
 


 
On Sun, May 2, 2010 at 9:22 AM, dennis wolfe <dwolfe@dropsheet.com> wrote:
 

Sevcon PMAC will go from F to R instantly.  Be sure to get the firmware version that has been updated to do this.
 
Denny
 
----- Original Message -----
From: mboucher99
Sent: Sunday, May 02, 2010 6:36 AM
Subject: [Electric Boats] controllor for mars brushless 48v

 

all,
just getting back to my search for a new controller for our mars 48v brushless - powering a 5,600 lbs 27' sloop. (we never hit the water last year)

we have an older controller that requires a delay between forward and reverse, making docking or mooring in our strong currents more adventuresome than the actual sailing. many recent posts seem to touch on this topic, as well as the equally fun one of drive belts riding off of edgeless pulleys) however, my electrical ignorance prevents me from gleaning the info i really need to make a decision. is there a consensus out there as to what might be the best (SIMPLE)option for us?
thanks!
mb in freeport maine


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