Minutes BWS Upgrade: Electro-Mechanical Design Meeting #2 -- 24^th July 2015 --

Participants: Bernd Dehning, Raymond Venness, Dmitry Gudkov, Jonathan Emery, Pierre-Jean Lapray, Luca Timeo, Jose Luis Sirvent

Agenda ( http://indico.cern.ch/event/435233/ ) :

PDF version here

1. Communications

• The new optical disk fixation has been tested, observed imperfections on holder, the piece needs to be re-machined.

2. Follow-up Open Actions

• No remarks on follow-up open actions

3. Motor Selection (D.Gudkov)

• From 6 Companies contacted for motor procurement 3 are interested (Alxion, Kollmorgen, Parker)
• Quotation from Alxion and Kollmorgen available, waiting for updated Parker quotation.

• 4 Possible motors compliant with our specifications
  • Alxion: 14S5TX2M (short) & 14S5TK4M (long)
  • Kollmorgen: KBM-35x02
  • Parker: NK620
• Motors delivery times (needed to consider holidays):
  • Off the shelf : 7..10 Weeks
  • Custom models : 10..16 Weeks
• Main Differences Custom vs Standard:
  • Samarium Cobalt magnets (and it’s fixation for vacuum compatibility, no glue)
  • Increasement of Air Gap by machining stator (0.5 to 0.7 mm = 5 to 10%torque decrease, info from Alxion)

• Open question: Spares politicy?
  • Buy a big amount of spares once VS Trust on companies availability guarantee
  • All contacted companies are relatively “Big”, production guaranteed for many years
  • Decision not taken here

4. Electrical Requirements and test setups (J.Emery)

• Motor Study:
  • Motor 14S5TK4M (long) deeply studied by Jonathan in terms of torke, speed and performance for SPS, LHC and PSB.
  • This motor would experience acceleration issues for the LHC configuration .
  • Longer active length improves torke.
  • Exist two versions of this motor (For torke and for Speed).
  • This motor is not suitable for 200rad/s , no torke is achieved at this speed, meaning that constant speed is not guaranteed. However, 140rad/s would be fine (but it’s slowlier than specified for the BWS).
  • The motor consists on 12 poles (Initial Parker motor had only 4), which means higher di/dt variations, moreover it has a very high inertia.

• Requirements:
  • BWS Prototype:
    • A mechanical piece is needed to keep the shaft in “Home position”, acting as angular reference to align properly the fork, motor stator/rotor, resolver, break and optical disk.
  • BWS Calibration Bench:
    • Both Linear stages must be on the same orientation
    • System needs to be properly aligned horizontally (to work on a table)
    • Fixation of optical parts needs to be defined.
    • Design needs to be reviewed Jonathan & Mechanics
    • Proposed the usage of two flanges with identical holes to align Laser system.

5. Test Planning (B.Dehning)

• No remarks on test planning

6. AOB

• Discussion:
  • New Optical disk:
  • New disk sent in September to CERN (a little sample to check quality)
  • Possibility of testing the reflectivity of such disk with the real optical system.
  • Check investigations on disks with micro holes.

• Decissions:
  • 2 Off the shelf motors + 2 Custom motors to be purchased: Alxion 14S5TX2M & Kollmorgen KBM-35x02.
  • Integration with Alxion 14S5TX2M .
  • Two test-benches as flexible as “Juan model” needs to be built.
  • Tests with original motors and stator machined (bigger air gap) motors to be done

• New Actions: