LBT PROJECT 2x8.4m TELESCOPE
	TECHNICAL SPECIFICATION FOR ROTATING ENCLOSURE GEARS AND MOTORS
	Doc. 301S001/A November 5, 1997 W. Gallieni and S. DeRigne

- INDEX :

0 - Introduction.
1 - Supply Description.
2 - Environmental Conditions.
2 - Delivery Conditions.

0 - INTRODUCTION.

For all the mechanical data used for the driving units dimensioning and selection, please refer to the Technical Report Doc. No. 301a002d. Those data have driven us to a first selection of 8 gear reduction units of the hollow shaft type, with overall transmission ratio 1 : 315, and nominal low speed shaft torque of 40000 Nm. These will be driven by 8 squirrel cage motors supplying 12,5 KW, complete with disc brake (DC actuated). The motors have been specified as over-sized from 16 HP to 20 HP to minimize the problems of overheating when operating at low speed. The motors will be supplied with external forced ventilation for cooling during low-speed operation. The brakes will be operable independently from the motor power. We prefer to have either 4 or 8 VFD units supplying individual motors or pairs of motors.

1 - SUPPLY DESCRIPTION.

1.1 Gear Boxes

G.S.M. MODENA
via Dino Lugli, no. 12
42100 Modena
ITALY
telephone: 39-59-365022
telefax: 39-59-280792

The locking of the gear hub on the wheel shaft must be realized in the version with RINGFEDER locking conical rings, as per the illustrations of the GSM catalogue enclosed. The verification of the gear size has to be done by the Manufacturer taking into account over the demanded torque, of the environmental conditions where the enclosure shall be installed as listed below.

The Manufacturer shall design, supply and assemble the flange adapter, the flexible joint between motor and gear.

With the Offer the Supplier of the Gears must supply the complete technical description of the gear boxes with the details of the coupling and flange for the motor, at present estimated to be the 160 L Size of the European Standard.

1.2 Motors

• squirrel cage motors, continuous duty
• totally enclosed
• class F insulation
• 460 VAC, 60 Hz, 3-phase Delta
• 20 HP (15 kW)
• 1800 rpm nominal speed
• flanged in vertical position
• brake
  • integral mount to motor
  • disc type
  • 24 VDC fail safe operation (brake engaged with power off)
  • capacity 81 Nm (60 Ft-lb)
• external cooling blower
  • single phase, 60 Hz
  • controlled by brake control output
• thermal protection by temperature sensors against overheating

With the Offer the Supplier of the Motors must supply the complete technical description of the Motor complete with the DC disc brake.

1.3 Inverters

• 460 VAC, 60 Hz, 3-phase Delta
• 1,2 - 60 Hz frequency range (with programmable maximum frequency)
• constant torque output
• 20 HP output capability per inverter using 8 inverters
  (or 40 HP per inverter if only 4 inverters used)
• programmable acceleration/deceleration rates
• brake control output

2 - ENVIRONMENTAL CONDITIONS

• Site Elevation over the sea level: +3200 m   (10500 feet)
• Storage temperature: from -30 up to +50 C
• Operating temperature: from -15 up to +25 C
• Storage pressure: from 500 up to 760 Torr
• Operating pressure: from 500 up to 600 Torr
• Storage humidity: from 5% up to 80%
• Operating humidity: from 5% up to 95%

3 - DELIVERY CONDITIONS

3.1 Delivery Time

Each Gear Reduction Unit shall be supplied completely assembled (and tested) with the relevant motor to the Bogie Manufacturer's (Costamasnaga) workshop within the 31 January 1998. Shipping costs are to be included in the Supply.

3.2 Delivery Location

COSTAMASNAGA S.P.A.
Via IV Novembre n. 2
Costa Masnaga, Lecco
ITALY
telephone:39-31-858111
telefax: 39-31-879332

After assembly with the Bogies, these units will be exported to Mt. Graham in Arizona to be installed on the enclosure of the Large Binocular Telescope.

Last modified: Wed Nov 5 16:11:10 1997