reduce the noice from the robot cabinet

[ATC_David]

here at the company, we have a Kuka KR 360-2 robot. We use it for testing at the moment, so no production. As such it is placed not in a noisy factory environment, but a relatively quiet space.

The robot is not that noisy, but once in a while the cooling of the cabinet is activated and it will make a whole lot of noise for about 15 minutes. Even though the robot is not used, the noise still stays present for the same amount of time.
We contacted kuka about this, but they do not want to help us in this matter.

Is there a way to alter the settings for the cooling, so it will stop sooner, or start at a higher temperature? Can this be done in the software? Or should we do a hardware alteration? (it is a krc2 cabinet.)

[mechrob]

When you go to: C --> KRC --> MADA --> STUE, can you tell us what the value is for the fan_follow_up_time?

With default settings the value is 1000 so the fan turns all the time. But when the connectors on the power supply are changed it is possible to change this value so the fan will only work when necessary.

I guess that this value is 15 (15 minutes) so you can change this value into 5. So it will only work for 5 minutes.
I don't think you can change it into "0" but you can try...

Good luck

[ATC_David]

The value is currently set to 5.0  (maybe it's 5 minutes instead of 15, it just seems a long time, i didn't actually time it. ;) )

If i set this to 0, will it nut run at all, or not run after it has reached the threshold?

As you can see below, it now starts at 44 degrees. What would be a safe value? 60? I'm reluctant to put this value too high.

=============================================================
REAL $FAN_FOLLOW_UP_TIME=5.0 ;NACHLAUFZEIT FUER DIE FAN-ANSTEUERUNG
INT $FAN_RED_LIMIT_TEMP=0 ;Reduktion der Schaltschwelle in Celsius fuer Schrankluefter (0 entspricht Schwelle von 44 Grad)
INT $MOTOR_RED_TEMP=0 ;Reduktion der Abschaltschwelle in Celsius fuer Motoren (0 entspricht Schwelle von 155 Grad abzueglich Messtoleranz)
=============================================================

[the leg]

you can change the fans to be temperature controlled

See below

Temperature controlled fan

The fan in the KRC-2 Cabinet runs, depending on the Cabinet Version, always or is switched by the power supply. The switch-on temperature is set to 44 (fixed value) degree Celsius (111.2 Fahrenheit).

Have a look at Connector X114 at the KPS

Current-state:
X 110 PIN 4 two cables connected (Cable lable: 1 and 3)

Target-state:
X 110 PIN 4 only one wire with the label 3 left
X 114 PIN 3 only one wire with the label 1 left   
This activates temperature controlling
You can set the switch-off-delay in the STEU\mada\machinen.dat file by setting the variable
-> $FAN_FOLLOW_UP_TIME =5.0  5-999 Minutes off-carriage; 1000 switches fan on constantly.
 

[SkyeFire]

We recently discovered something curious on this subject.  The KRC2 cabinet appears to have a design that produces cavitation noises in the airflow through the "hollow" walls of the cabinet.  This issue only appear to show up in cabinets that were built for larger-payload robots (KR360s and higher), which have a larger main heat exchanger fan (located in the bottom of the cabinet, behind the exterior panel.  This causes a loud "rumbling" in the airflow -- sometimes constant, sometimes cyclic (possibly related to the thermostat control of the fans).

For some reason, the noise seems most closely related to the vent in the top of the cabinet, on the same side as the main power disconnect (the left side, as seen by someone standing in front of the cabinet door).  We found that closing this top vent (NOT the top side vent) with something, like a long strip of wide masking tape, reduced the cavitation noises a great deal.  We eventually had the primary heat exchanger fans replaced with the smaller models used by robots like the KR240, and experienced a noise reduction of 50% or better.

However, I should point out that this may not be a good idea for everyone.  We could do it since our KR360s are lightly loaded, and working at relatively low speeds and duty cycles.  For robots working at high speed for long extended durations, especially in hot environments, taking these actions could pose a potential risk to the equipment from overheating.

Still, I'd like to hear if anyone else finds the same effect applies to their KRC2s.