BUSCH COBRA NC 0500 B User manual

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COBRA
Dry Screw Vacuum Pumps
NC 0500 B
Instruction Manual
0870549522 | A0002_en | Original instructions 28/02/2022

Table of Contents
2 | 36 Instruction Manual COBRA NC 0500 B_EN_en
Table of Contents
1 Safety..................................................................................................................................................................... 3
2 Product Description............................................................................................................................................. 4
2.1 Operating Principle ............................................................................................................................................. 5
2.2 Application ........................................................................................................................................................... 5
2.3 Start Controls....................................................................................................................................................... 5
2.4 Standard Features............................................................................................................................................... 5
2.4.1 Water Cooling........................................................................................................................................ 5
2.4.2 Temperature Switch ............................................................................................................................. 6
2.4.3 Thermometer ........................................................................................................................................ 6
2.4.4 Silencer................................................................................................................................................... 6
2.4.5 Sealing Systems..................................................................................................................................... 6
3 Transport .............................................................................................................................................................. 7
4 Storage .................................................................................................................................................................. 8
5 Installation ........................................................................................................................................................... 9
5.1 Installation Conditions........................................................................................................................................ 9
5.2 Connecting Lines / Pipes .................................................................................................................................... 9
5.2.1 Suction Connection............................................................................................................................... 10
5.2.2 Discharge Connection .......................................................................................................................... 10
5.2.3 Cooling Water Connection................................................................................................................... 11
5.3 Filling Oil............................................................................................................................................................... 12
5.4 Filling Cooling Liquid........................................................................................................................................... 13
5.5 Electrical Connection .......................................................................................................................................... 13
5.5.1 Wiring Diagram Three-Phase Motor (Pump Drive)........................................................................... 14
5.6 Electrical Connection of the Monitoring Devices ............................................................................................ 15
5.6.1 Wiring Diagram Temperature Switch................................................................................................. 15
6 Commissioning..................................................................................................................................................... 16
7 Maintenance......................................................................................................................................................... 18
7.1 Draining the Cooling Water ............................................................................................................................... 18
7.2 Maintenance Schedule ....................................................................................................................................... 19
7.3 Oil Level Inspection............................................................................................................................................. 19
7.4 Cooling Liquid Level Inspection......................................................................................................................... 20
7.5 Oil Change............................................................................................................................................................ 20
7.6 Cooling Liquid Change ....................................................................................................................................... 23
8 Overhaul................................................................................................................................................................ 24
9 Decommissioning................................................................................................................................................. 25
9.1 Dismantling and Disposal .................................................................................................................................. 25
10 Spare Parts............................................................................................................................................................ 26
11 Troubleshooting................................................................................................................................................... 27
12 Technical Data...................................................................................................................................................... 29
13 Cooling Liquid....................................................................................................................................................... 30
14 Oil........................................................................................................................................................................... 31
15 EU Declaration of Conformity............................................................................................................................. 32
16 UK Declaration of Conformity ............................................................................................................................ 33

Safety | 1
Instruction Manual COBRA NC 0500 B_EN_en 3 | 36
1 Safety
Prior to handling the machine, this instruction manual should be read and understood. If anything
needs to be clarified, please contact your Busch representative.
Read this manual carefully before use and keep for future reference.
This instruction manual remains valid as long as the customer does not change anything on the
product.
The machine is intended for industrial use. It must be handled only by technically trained personnel.
Always wear appropriate personal protective equipment in accordance with the local regulations.
The machine has been designed and manufactured according to state-of-the-art methods.
Nevertheless, residual risks may remain. This instruction manual highlights potential hazards where
appropriate. Safety notes and warning messages are tagged with one of the keywords DANGER,
WARNING, CAUTION, NOTICE and NOTE as follows:
DANGER
... indicates an imminent dangerous situation that will result in death or serious injuries if not
prevented.
WARNING
... indicates a potentially dangerous situation that could result in death or serious injuries.
CAUTION
... indicates a potentially dangerous situation that could result in minor injuries.
NOTICE
... indicates a potentially dangerous situation that could result in damage to property.
NOTE
... indicates helpful tips and recommendations, as well as information for efficient and
trouble-free operation.

2 | Product Description
4 | 36 Instruction Manual COBRA NC 0500 B_EN_en
2 Product Description
EB
IN
OSG
OFPCWI CWO
PMR
TM
CLF
CLP
MP
SV CLG
TS
ODP
CLD
NP
OUTODP, MP SICLD ECO
OFP
Description
CLD Cooling liquid drain plug CLF Cooling liquid fill plug
CLG Cooling liquid sight glass CLP Cooling liquid pump
CWI Cooling water inlet CWO Cooling water outlet
EB Eye bolt ECO Electrical connection
IN Suction connection MP Magnetic plug
NP Nameplate ODP Oil drain plug
OFP Oil fill plug OSG Oil sight glass
OUT Discharge connection PMR Plug for manual rotation of rotors
SI Silencer SV Safety valve
TM Thermometer TS Temperature switch
NOTE
Technical term.
In this instruction manual, we consider that the term ‘machine’ refers to the ‘vacuum pump’.

Product Description | 2
Instruction Manual COBRA NC 0500 B_EN_en 5 | 36
NOTE
Illustrations
In this instruction manual the illustrations may differ from the machine appearance.
2.1 Operating Principle
The machine works on the one-stage, twin-screw pump principle.
Two screw rotors are rotating inside the cylinder. The pumped medium is trapped between the
cylinder and screw chambers, compressed, and transported to the gas outlet. During the
compression process, the two screw rotors do not come into contact with each other nor with the
cylinder. There is no need for a lubrication or an operating fluid in the compression chamber.
2.2 Application
The machine is intended for the suction of air and other dry, non-aggressive, non-toxic and non-
explosive gases.
Conveying of other media leads to an increased thermal and/or mechanical load on the machine
and is permissible only after a consultation with Busch.
The machine is capable of maintaining ultimate pressure, see Technical Data [➔29].
The machine is suitable for continuous operation.
The machine is suitable for use in an installation with a vacuum chamber volume no larger than 80
litres.
Permitted environmental conditions, see Technical Data [➔29].
2.3 Start Controls
The machine comes without start controls. The control of the machine is to be provided in the
course of installation.
The machine can be optionally equipped with a starter unit or a variable speed drive.
2.4 Standard Features
2.4.1 Water Cooling
The machine is cooled by a cooling liquid circuit in the cylinder cover and cylinder.
The cooling liquid pump (CLP) allows a recirculating flow in the cooling liquid chamber.
The cooling liquid is cooled by an internal heat exchanger. This cooling system integrates the
cooling of the water-cooled motor and must be connected to the water main.

2 | Product Description
6 | 36 Instruction Manual COBRA NC 0500 B_EN_en
2.4.2 Temperature Switch
The temperature switch monitors the oil temperature of the machine.
The machine must be stopped when the temperature switch trips (100 °C).
2.4.3 Thermometer
The thermometer allows a visual display of the cooling liquid temperature.
2.4.4 Silencer
The silencer reduces the exhaust gas noise at the machine discharge (OUT).
2.4.5 Sealing Systems
The machine is equipped with labyrinth seals on the motor side and suction side.
Sealing systems prevent the process gas going to the bearings chambers.

Transport | 3
Instruction Manual COBRA NC 0500 B_EN_en 7 | 36
3 Transport
WARNING
Suspended load.
Risk of severe injury!
●Do not walk, stand or work under suspended loads.
WARNING
Lifting the machine using the motor eye bolt.
Risk of severe injury!
●Do not lift the machine using the eye bolt fitted to the motor. Only lift the machine as shown.
NOTICE
In case the machine is already filled with oil.
Tilting a machine that is already filled with oil can cause large quantities of oil to ingress into
the cylinder.
●Drain the oil prior to every transport or always horizontally transport the machine.
●To find out the weight of the machine, refer to the chapter Technical Data [➔29] or the
nameplate (NP).
1
2
Description
1 Length of slings: 3x 600 mm 2 Optional sling
●Check the machine for transport damage.
If the machine is secured to a base plate:
●Remove the machine from the base plate.

4 | Storage
8 | 36 Instruction Manual COBRA NC 0500 B_EN_en
4 Storage
●Seal all apertures with adhesive tape or reuse provided caps.
If the machine is to be stored for more than 3 months:
●Wrap the machine in a corrosion inhibiting film.
●Store the machine indoors, dry, dust free and if possible in original packaging preferably at
temperatures between 5 ... 55 °C.
●To avoid frost damage, drain the cooling water. See Maintenance [➔18].
NOTICE
Long storage time.
Risk of damage to the machine!
●If the machine is equipped with oil lubricated mechanical seals, we recommend to completely fill
the oil chamber before a long storage, see “Oil filling” in chapter Oil Change [➔20]. This protects
the mechanical seals during a long storage. Use the standard pump oil, see chapter Oil [➔31].
●Before restarting the machine, drain the oil to the normal oil level, see “Oil draining” in chapter Oil
Change [➔20].

Installation | 5
Instruction Manual COBRA NC 0500 B_EN_en 9 | 36
5 Installation
5.1 Installation Conditions
WARNING
If the machine is installed in a potentially explosive environment, or if the machine is used to
draw toxic, inflammable or non-inert gases:
Risk of injuries!
Risk of death!
●Ensure that the machine complies with all local, national rules and safety regulations.
NOTICE
Use of the machine outside of the permitted installation conditions.
Risk of premature failure!
Loss of efficiency!
●Take care that the installation conditions are fully complied with.
●Make sure that the environment of the machine is not potentially explosive.
●Make sure that the ambient conditions comply with the Technical Data [➔29].
●Make sure that the environmental conditions comply with the protection class of the motor and
the electrical instruments.
●Make sure that the vacuum chamber volume does not exceed 80 liters.
●Make sure that the installation space or location is protected from weather and lightning.
●Make sure that the installation space or location is vented such that sufficient cooling of the
machine is provided.
●Make sure that the oil sight glass (OSG) remains easily visible.
●Make sure that enough space remains for maintenance work.
●Make sure that the machine is placed or mounted horizontally, a maximum of 1° in any direction
is acceptable.
●Check the oil level, see Oil Level Inspection [➔19].
●Check the cooling liquid level, see Cooling Liquid Level Inspection [➔20].
●Make sure that the cooling water complies with the requirements, see Cooling Water Connection
[➔11].
If the machine is installed at an altitude greater than 1000 meters above sea level:
●Contact your Busch representative, the motor should be derated or the ambient temperature
limited.
5.2 Connecting Lines / Pipes
●Remove all protective covers before installation.
●Make sure that the connection lines cause no stress on the machine‘s connection; if necessary use
flexible joints.
●Make sure that the line size of the connection lines over the entire length is at least as large as
the connections of the machine.

5 | Installation
10 | 36 Instruction Manual COBRA NC 0500 B_EN_en
In case of long connection lines it is advisable to use larger line sizes in order to avoid a loss of
efficiency. Seek advice from your Busch representative.
5.2.1 Suction Connection
WARNING
Unprotected suction connection.
Risk of severe injury!
●Do not put hand or fingers in the suction connection.
NOTICE
Ingress of foreign objects or liquids.
Risk of damage to the machine!
If the inlet gas contains dust or other foreign solid particles:
●Install a suitable filter (5micron or less) upstream from the machine.
Connection size(s):
– G2
If the machine is used as part of a vacuum system:
●Busch recommends the installation of an isolation valve in order to prevent the machine from
turning backwards.
5.2.2 Discharge Connection
Connection size(s):
– G1 1/2
●Make sure that the discharged gas will flow without obstruction. Do not shut off or throttle the
discharge line or use it as a pressurised air source.
●Make sure that the counter pressure (also termed back pressure) at the discharge connection
(OUT) does not exceed the maximum allowable discharge pressure, see Technical Data [➔29].

Installation | 5
Instruction Manual COBRA NC 0500 B_EN_en 11 | 36
5.2.3 Cooling Water Connection
CWI CWO
Description
CWI Cooling water inlet CWO Cooling water outlet
●Connect the cooling water connections (CWI / CWO) to the water supply.
Connection size:
– G1/4 for the cooling water inlet (CWI)
– R1/2 for the cooling water outlet (CWO)
●Make sure that the cooling water complies with the following requirements:
Supply capacity l/min 5
Water pressure bar 3 ... 6
Supply temperature °C +10 ... +30
Required pressure differential across supply
and return
bar ≥ 1
●To reduce the maintenance effort and ensure a long product lifetime we recommend the
following cooling water quality:
Hardness mg/l (ppm) < 90
Properties Clean & clear
PH value 7 ... 8
Particle size µm < 200
Chloride mg/l < 100
Electrical conductivity µS/cm ≤ 100
Free chloride mg/l < 0.3
Materials in contact with the cooling water Stainless steel
NOTE
Water hardness unit conversion.
1 mg/l (ppm) = 0.056 °dh (german degree) = 0.07 °e (english degree) = 0.1 °fH (french degree)

5 | Installation
12 | 36 Instruction Manual COBRA NC 0500 B_EN_en
5.3 Filling Oil
NOTICE
Use of an inappropriate oil.
Risk of premature failure!
Loss of efficiency!
●Only use an oil type which has previously been approved and recommended by Busch.
For oil type and oil capacity see Technical Data [➔29] and Oil [➔31].

Installation | 5
Instruction Manual COBRA NC 0500 B_EN_en 13 | 36
When the oil filling is achieved:
●Write down the oil change date on the sticker.
Last oil change
__ / __ / ____
Oil type see nameplate
Change interval see
instruction manual
If there is no sticker (part no. 0565 568 959) on the machine:
●Order it from your Busch representative.
5.4 Filling Cooling Liquid
For cooling liquid type and cooling liquid capacity see Technical Data [➔29] and Cooling Liquid
[➔30].
5.5 Electrical Connection
DANGER
Live wires.
Risk of electrical shock.
●Electrical installation work must only be executed by qualified personnel.
●Make sure that the power supply for the motor is compatible with the data on the nameplate of
the motor.
●The electrical installation must comply with applicable national and international standards.

5 | Installation
14 | 36 Instruction Manual COBRA NC 0500 B_EN_en
●Provide a lockable disconnect switch on the power line so that the machine is completely secured
during maintenance tasks.
●Provide an overload protection according to EN 60204-1 for the motor.
●Make sure that the motor of the machine will not be affected by electric or electromagnetic
disturbance from the mains; if necessary seek advice from Busch.
●Connect the protective earth conductor.
●Electrically connect the motor.
NOTICE
The admissible motor nominal speed exceeds the recommendation.
Risk of damage to the machine!
●Check the admissible motor nominal speed (nmax) on the nameplate of the machine (NP).
●Make sure to comply with it.
●Consult the Technical Data [➔29] to get more information.
NOTICE
The motor frequency is below 20 Hz.
Risk of damage to the machine!
●The motor nominal speed must always be higher than 1200 min-1 (20 Hz).
5.5.1 Wiring Diagram Three-Phase Motor (Pump Drive)
Delta connection (low voltage): Star connection (high voltage):
U1
V1
W1
U2
V2
W2
Earth
L1
L3
L2
U1
V1
W1
U2
V2
W2
Earth
L1
L3
L2
Earth Earth
NOTICE
Incorrect direction of rotation.
Risk of damage to the machine!
●Operation in the wrong direction of rotation can destroy the machine in a short time! Prior to
start-up, ensure that the machine is operated in the right direction.
The intended rotation direction of the motor is defined by the illustration below:

Installation | 5
Instruction Manual COBRA NC 0500 B_EN_en 15 | 36
●Jog the motor briefly.
●With a phase rotation tester, check if the wiring corresponds to the correct direction of rotation.
If the rotation of the motor must be changed:
●Switch any two of the motor phase wires.
5.6 Electrical Connection of the Monitoring Devices
NOTE
In order to prevent potential nuisance alarms, Busch recommends that the control system is
configured with a time delay of at least 20 seconds.
5.6.1 Wiring Diagram Temperature Switch
Part no.: 0651 541 566
U = 250 VAC ; I = 2.5 A ► cosφ = 1
U = 250 VAC ; I = 1.6 A ► cosφ = 0.6
U = 48 VDC ; I = 1.25 A
Contact : Normally closed
Switch point: Ttrip = 100 °C
2
1
T
1 = White ; 2 = Brown

6 | Commissioning
16 | 36 Instruction Manual COBRA NC 0500 B_EN_en
6 Commissioning
NOTICE
The machine can be shipped without oil.
Operation without oil will ruin the machine in short time!
●Prior to commissioning, the machine must be filled with oil, see Filling Oil [➔12].
NOTICE
The machine can be shipped without cooling liquid.
Operation without cooling liquid will ruin the machine in short time!
●Prior to commissioning, the machine must be filled with cooling liquid, see Filling Cooling Liquid
[➔13].
NOTICE
Lubricating a dry running machine (compression chamber).
Risk of damage to the machine!
●Do not lubricate the compression chamber of the machine with oil or grease.
CAUTION
During operation the surface of the machine may reach temperatures of more than 70°C.
Risk of burns!
●Avoid contact with the machine during and directly after operation.
CAUTION
Noise of running machine.
Risk of damage to hearing!
If persons are present in the vicinity of a non noise insulated machine over extended periods:
●Make sure that ear protection is being used.
●Make sure that the installation conditions (see Installation Conditions [➔9]) are met.
●Turn on the water supply.
●Switch on the machine.
●Make sure that the maximum permissible number of starts does not exceed 6 starts per hour.
Those starts should be spread within the hour.
●Make sure that the operating conditions comply with the Technical Data [➔29].
●After a few minutes of operation, perform an Oil Level Inspection [➔19].
●After a few minutes of operation, perform a Cooling Liquid Level Inspection [➔20].
As soon as the machine is operated under normal operating conditions:

Commissioning | 6
Instruction Manual COBRA NC 0500 B_EN_en 17 | 36
●Measure the motor current and record it as reference for future maintenance and
troubleshooting work.

7 | Maintenance
18 | 36 Instruction Manual COBRA NC 0500 B_EN_en
7 Maintenance
WARNING
Machines contaminated with hazardous material.
Risk of poisoning!
Risk of infection!
If the machine is contaminated with hazardous material:
●Wear appropriate personal protective equipment.
CAUTION
Hot surface.
Risk of burns!
●Prior to any action requiring touching the machine, let the machine cool down first.
NOTICE
Using inappropriate cleaners.
Risk of removing safety stickers and protective paint!
●Do not use incompatible solvents to clean the machine.
CAUTION
Failing to properly maintain the machine.
Risk of injuries!
Risk of premature failure and loss of efficiency!
●Maintenance work must only be executed by qualified personnel.
●Respect the maintenance intervals or ask your Busch representative for service.
●Shut down the machine and lock against inadvertent start up.
●Turn off the water supply.
●Vent the connected lines to atmospheric pressure.
If necessary:
●Disconnect all connections.
7.1 Draining the Cooling Water
●Make sure that the vacuum pump is switched off and cannot accidentally be switched on again.
●Put a drain tray underneath the cooling water connections (CWI, CWO).
●Disconnect the cooling water connections (CWI, CWO).
●Use compressed air to force the remaining cooling water out of the cooling water circuit. Blow in
compressed air into CWI during 30 seconds until it exits dry.

Maintenance | 7
Instruction Manual COBRA NC 0500 B_EN_en 19 | 36
7.2 Maintenance Schedule
The maintenance intervals depend very much on the individual operating conditions. The intervals
given below are considered as starting values which should be shortened or extended as
appropriate. Particularly harsh applications or heavy duty operation, such as high dust loads in the
environment or in the process gas, other contamination or ingress of process material, can make it
necessary to shorten the maintenance intervals significantly.
Interval Maintenance work
Monthly ●Check the oil level, see Oil Level Inspection [➔19].
●Check the cooling liquid level, see Cooling Liquid Level
Inspection [➔20].
●Check the machine for oil leaks - in case of leaks have the
machine repaired (contact Busch).
Yearly ●Carry out a visual inspection and clean the machine from
dust and dirt.
●Check the electrical connections and the monitoring
devices.
Every 1000 hours. ●Check the silence (SI) and clean it if necessary.
Every 5000 hours or after 1 year ●Change the oil of the gear and bearing housings (both
sides), see Oil Change [➔20].
●Change the cooling liquid, see Cooling Liquid Change
[➔23].
●Clean the magnetic plugs (MP).
Every 16000 hours or after 4
years
●Have a major overhaul on the machine (contact Busch).
7.3 Oil Level Inspection
●Shut down the machine.
●When the machine is stopped, wait 1 minute before checking the oil level.
●Make sure that the oil level is between the middle of the oil sight glass and 3mm above it.
●Fill up if necessary, see Oil Filling [➔12].

7 | Maintenance
20 | 36 Instruction Manual COBRA NC 0500 B_EN_en
7.4 Cooling Liquid Level Inspection
●Shut down the machine.
●Fill up if necessary, see Filling Cooling Liquid [➔13].
7.5 Oil Change
NOTICE
Use of an inappropriate oil.
Risk of premature failure!
Loss of efficiency!
●Only use an oil type which has previously been approved and recommended by Busch.
MP