Hammer N4400 Bandsaw noise

[ScouseKev]

Can anyone shed light on the noise on my Hammer bandsaw please??

When i switch the power off, the blade comes to a stop fairly quick due to the electric brake...but the brake buzz continues for about another 7 seconds or so.

The saw works perfectly.

Any Hammer owners experienced this??

Thanks

 

[HappyHacker]

The brake electronics operate for a fixed time as they cannot detect the blade has stopped so it is set to provide braking DC current for a time longer than the actual stop time.

 

[custard]

Any Hammer owners experienced this??

Yes, exactly that. But I've been clueless why until HH's explanation!

 

[shed9]

Any Hammer owners experienced this??

Yes, exactly that. But I've been clueless why until HH's explanation!

+1, mine does that and never knew why until now.

Actually started having issues starting up a few days ago, replaced the starter cap and checked the rotor which is fine. Problem is I need to press the start button a few times before it kicks in. Don't suppose any other N4400 users can shed light.

Sorry to hijack the thread a little ScouseKev

 

[mbartlett99]

Errmmm, bit more hijacking - sorry Mine arrives in a couple of weeks any tips or tricks - like humming electrics?

 

[custard]

Actually started having issues starting up a few days ago, replaced the starter cap and checked the rotor which is fine. Problem is I need to press the start button a few times before it kicks in. Don't suppose any other N4400 users can shed light.

Sorry to hijack the thread a little ScouseKev

I'm not an electrician, but one thing I've heard is that you should always turn off the N4400 with the red off button, not by switching off at a mains switch. I've heard that using the mains switch can over time introduce all sorts of electrical issues. I've also been told with respect to my bigger Felder equipment that you should hold the on button for a second or two when starting up until the planer, saw, spindle etc has spun up to working speed. In other words you don't just jab the on button, I've no idea if this also applies to the N4400 but I do it anyway. I've run this particular N4400 every day for about five years and it's never missed a beat, I see some in other workshops that have been worked hard for much much longer and they're also delivering yeoman service.

 

[decas]

+ another one. My C3-31 combination makes the same buzzing sound when switched off.

As for starting Hammer machines, sorry if I am telling you how to suck eggs but the start button needs to be kept pressed for a couple of seconds until the motor has run up to speed (at least on my single phase machines).

Cheers, Dave

 

[decas]

I think Peter Sefton posted some time ago about problems with electrics caused by isolating the machine too soon after switching off.

Dave

 

[shed9]

Actually started having issues starting up a few days ago, replaced the starter cap and checked the rotor which is fine. Problem is I need to press the start button a few times before it kicks in. Don't suppose any other N4400 users can shed light.

Sorry to hijack the thread a little ScouseKev

I'm not an electrician, but one thing I've heard is that you should always turn off the N4400 with the red off button, not by switching off at a mains switch. I've heard that using the mains switch can over time introduce all sorts of electrical issues. I've also been told with respect to my bigger Felder equipment that you should hold the on button for a second or two when starting up until the planer, saw, spindle etc has spun up to working speed. In other words you don't just jab the on button, I've no idea if this also applies to the N4400 but I do it anyway. I've run this particular N4400 every day for about five years and it's never missed a beat, I see some in other workshops that have been worked hard for much much longer and they're also delivering yeoman service.

I always use the saw's switch gear holding the start until at full speed and switching off with the stop button. Like yours it's been faultless but it's showing this issue now, I don't momentarily push to start with this issue, I hold until it finally starts up.

I also run a Hammer K3 and an A3 in the same way and no problems with them to date.

The only thing that seems to stick out as a possible route to the issue is there is some circuitry in the switch gear box that looks like the logic to control the braking. Might give Felder a call and ask them if this is a known issue.

Thanks Custard and Dave.

 

[Peter Sefton]

My Hammer and Felder machines all make a bussing noise after switching off with the exception of my old A3 41 which stops via natural run down rather than electric braking.
The braked machines should not be isolated until the buzzing has stopped and the electrical system has done its black magic. I understand the capacitors need to discharge the energy. One of my past students was always in a rush and isolated immediately after switching off, within a month of him joining the workshop a brake board needed replacing on the 4400 otherwise it was a faultless machine. You may need to check with Felder as to your own machine, my older Hammer kit needed a dab push start, most of the newer kit needs to be held in on start up. If you get it wrong you can blow the capacitors.

Cheers Peter

 

[shed9]

Just raised a ticket with Felder.

Thanks people (and apologies once again Scouse Kev) for jumping in.

I will report back when resolved in case it is helpful for others.

 

[mbartlett99]

Not to do with electrics but is the Felder extension table for the N4400 just an Aigner standard part or specially made? Buying from Felder isn't exactly cheap after all.

 

[shed9]

Not to do with electrics but is the Felder extension table for the N4400 just an Aigner standard part or specially made? Buying from Felder isn't exactly cheap after all.

I believe it is custom to Felder as I order quite a bit of extrusion and I've never seen the rail available off the shelf and the tables themselves are machined to mate to that rail. That said, this doesn't mean you can't buy it from the same source, just don't know where that is.

 

[SamTheJarvis]

I know it's frowned upon to bring back an old thread but the solution wasn't identified successfully.

The brake board has two potentiometers, one for brake time and one for brake current. These are easy to adjust, aiming for 3-5 seconds stop time. Too much current can damage the windings and is unnecessary. It's also not great to be braking for longer than necessary, thyristor based DC braking is a bit of a hack and relies on mindful configuration.

If the brake board doesn't indicate which potentiometer is which, it's safe to tweak one slightly to identify.

 

[Blister]

My one does it as well , The noise continues after tha blade has stopped