?[Edited Message Follows]
[Reason: Added brake board to the response]

JP,

The tech has a point but likely did not communicate it well. Motors have service/duty ratings from S1 to S10. My Dual 51 is 7.35 KW S6-40%. Here is the explanation.

S1 Continuous duty The motor operates at a continuous load for sufficient time to enable machine to reach thermal equilibrium. S2 Short Time duty Operation at a load for a time not sufficient to reach thermal equilibrium, followed by enough time for the motor to cool down. S3 Intermittent periodic duty Series of identical duty cycles each a constant load for a period, followed by a rest period. Thermal equilibrium is not reached during the cycle. S4 Intermittent periodic duty with starting Similar to S3, but there is a significant starting time within the periodic operation. S5 Intermittent periodic duty with electric braking Sequence of identical duty cycles - starting, operation, braking and rest.? Again thermal equilibrium is not reached. S6 Continuous operation periodic duty Identical duty cycles with a period at load followed by a period at no load.? Difference between S1 is that the motor runs at no-load, without actual stopping. S7 Continuous operation periodic duty with electric braking As per S6, but with a?significant starting and electric breaking periods.? Again motor operates at no-load for? period instead of?stopped. S8 Continuous operation periodic duty with related load/speed changes Series of identical repeating duty cycles, where within each cycle the motor operates at several different load levels and speed. There is not stopped time and thermal equilibrium is not reached. S9 Duty with non-periodic load and speed variations Load and speed vary periodically within the permissible operating range. Frequent overloading may occur. S10 Duty with discrete constant loads and speeds Duty with discrete number of load/speed combinations, with these maintained long enough to reach thermal equilibrium.

Understanding Motor Duty Rating ( https://myelectrical.com/notes/entryid/106/understanding-motor-duty-rating )
myelectrical.com ( https://myelectrical.com/notes/entryid/106/understanding-motor-duty-rating )

Not sure what latest Dual 51 electronics are like but if I have to guess the circuit board tech referred to is likely the brake board. It would get hot with repetitive braking and so would the motor as it is braked with DC current injection.

As for fuse, I imagine we are talking about thermal fuse in the motor. If the motor did not start it likely got hot and needed to cool down to reset the thermal fuse.

As Lucky mentioned, the combo machine is meant to be used where switching function requires motor turn off. This should be fine. Just don’t over do it.

Let me know if you still have a question.

Imran Malik
https://www.facebook.com/groups/362481112015700/?ref=share

On Feb 6, 2024, at 11:48?PM, jppetricca@... wrote:

Hi Guys,

I have a question about our Dual 51. It’s nearly brand new, probably used less than 15 times, as we rarely mill lumber and when we do, it’s often not a lot.

We’ve been using it with our interns over the last two weeks, and recently, it seems like it blows a fuse when trying to turn it on sometimes. I called Felder, and the tech said it’s because you shouldn’t turn the blade on and off very often. He suggested keeping the blade running and, when shutting the machine off, keeping it off for 10 minutes to avoid damaging the circuit board. Because these young men are novice woodworkers and we needed to pause often to give instruction, we were shutting the blade off and turning it back on more frequently than his 10-minute rule.

What are your thoughts on whether this should be happening, and if you all have experience with how often we should be able to turn the blade on and off? I understand it’s best to keep the motor running, but for such an industrial machine, it seems odd this happened with very little use.

Any input would be greatly appreciated.

Thanks,
JP