You want to have a disconnect directly from the power source?
Find out what the total power draw of the motor is and find a connector that is at LEAST 50% higher rating. Most will say 100% over total power draw...I would think 50% should be safe...cheaper too.
That 6A connector would turn into a bowl of plastic soup in 5 min after drawing current to run that motor if they are asking for a 50 amp breaker.
If you see something with an inductive rating and a resistive rating, the resistive rating is what you are looking for. A inductive rating will always be higher because it's only a large momentary surge of power..only pay attention to the resistive rating.
Your load is going to be a pure resistance load (DC) you don't have to factor in inductance.