OF 1400 variable speed problem?

[promark747]

Hello,

First post here...seems like a great place with loads of info.

I'm a new OF 1400 owner (as of yesterday) and as I've started the initial examination of the tool, I noticed that the sound of the motor does not change at all from speed setting 1, until I get to 4 or 5 on the dial.  Is this normal?  The only way I know to "measure" that the speed is actually increasing is audibly, and for the life of me I can't tell any difference until the dial gets to about 5.  At that point the frequency definitely ramps up gradually until the max setting.  I assumed the speed (and sound) would change along the entire range of the dial.  Is this normal or do I have a defective unit?

Thanks,
Brian

 

[Brice Burrell]

Brian, first, welcome to the FOG. Yes, this is perfectly normal. With no load in the lower speed settings there won't be much if any noticeable difference in sound. When routing (under load) your see and hear a difference.

 

[promark747]

Great news -- thanks Brice for the quick response.

 

[Rick Christopherson]

I disagree. I believe that you should be able to hear some audible change in the motor as you change speeds at the lower settings. The slower you rotate the dial, the less noticeable it will be, but it should still be noticeable.

However, if the situation is present, it does not necessarily mean a significant problem. Before getting too concerned about it, simply exercise the speed dial back and forth to make sure the wiper on the variable resistor is making good contact. As a brand new tool with no usage, it is possible that the wiper has been sitting in one place for so long that it doesn't make proper contact through the rest of its movement.

You have a 3 year warranty and the first year includes shipping, so you don't need to panic about sending it back until you are fully sure there is an actual problem. If there is a problem, it will be fully covered.

 

[Brice Burrell]

Rick, I'm guessing Brain made the speed adjustment without a bit in the tool. If that's the case it's pretty easy to think the variable speed function isn't working correctly in the lower settings.

 

[Rick Christopherson]

The unseen and mythical Festool tool god has spoken to me in my dreams and corrected me of my previous statements. (You might know him as David).  [big grin]

Apparently it is true on some of the tools, such as the router, there is little or no difference between the lower speed settings when there is no load on the motor. There is enough rotational energy in the armature that even the short pulse from the PWM module is enough to spin it faster than it needs to be when there is no load to slow it down.

 

[harry_]

Makes sense to me.

 

[promark747]

Would "load" mean just having a bit installed or would it mean actual cutting?  I inserted one of my biggest bits and let it run (without routing anything), but there was still no audible difference between 1 and about 4.5 on the dial.

I'd be interested to hear from other owners of this particular model to see if theirs act the same.

Thanks,
Brian

 

[Brice Burrell]

Would "load" mean just having a bit installed or would it mean actual cutting?  I inserted one of my biggest bits and let it run (without routing anything), but there was still no audible difference between 1 and about 4.5 on the dial.

I'd be interested to hear from other owners of this particular model to see if theirs act the same.

Thanks,
Brian

I would think you would hear some difference with a large bit. Of course, that depends on your definition of a large bit. Don't be afraid to use the router, it will be obvious if there is a problem with the variable speed function while routing at different settings.

 

[Rickfisher]

I have an OF-1400.. I went and tried the exact test.. Its exactly the same.. No audible change in sound until you hit 5 on the scale..

My OF-1400 has a large Freud 1/2" Bit in the collet right now..

 

[Dave Ronyak]

Why not simply try using that new OF 1400 with a bit in some wood and trying different speed dial settings to see if the motor sound pitch varies while it is under real load?  I have an OF 1400 and the speed does audibly change even when there is only a 1/4 inch bit installed, but as others have written there is not much difference in pitch as the speed dial is slowly turned from 1 until I reach 3 or 4 on the dial.  At least one of my Festool RO sanders responds much the same when free wheeling in the air.  In contrast, with my PC 7518 and Freud 13A router, the pitch of the motor clearly changes immediately when the speed dial is changed even when the router is not under load.

Dave R.