BUSCH COBRA DX 0650 A User manual

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COBRA
Dry Screw Vacuum Pumps
DX 0650 A, DX 0950 A
Air-Cooled Version (ACV)
Instruction Manual
2000090907 | -_en-US | Original instructions 6/14/2023

Table of Contents
2 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
Table of Contents
1 Safety ..................................................................................................................................................................... 4
2 Product Description ............................................................................................................................................. 5
2.1 Operating Principle............................................................................................................................................. 7
2.2 Intended Use ....................................................................................................................................................... 7
2.3 Standard Features............................................................................................................................................... 8
2.3.1 Air Cooling............................................................................................................................................. 8
2.3.2 Temperature Switch............................................................................................................................. 8
2.3.3 Sealing Systems .................................................................................................................................... 8
2.4 Optional Accessories........................................................................................................................................... 9
2.4.1 Gas Ballast Valve................................................................................................................................... 9
2.4.2 Silencer .................................................................................................................................................. 9
2.4.3 Barrier Gas System............................................................................................................................... 9
2.4.4 Electro-pneumatic Inlet Valve ............................................................................................................. 9
2.4.5 OTTO IoT Box ........................................................................................................................................ 10
2.4.6 I/O and Communication Port.............................................................................................................. 10
2.4.7 Main Power Switch / Breaker.............................................................................................................. 13
2.4.8 Harting Connector................................................................................................................................ 13
3 Transport............................................................................................................................................................... 14
4 Storage................................................................................................................................................................... 15
5 Installation............................................................................................................................................................ 16
5.1 Installation Conditions ....................................................................................................................................... 16
5.2 Connecting Lines / Pipes .................................................................................................................................... 17
5.2.1 Suction Connection .............................................................................................................................. 17
5.2.2 Discharge Connection.......................................................................................................................... 18
5.2.3 Barrier Gas System Connection (Optional)........................................................................................ 19
5.2.4 Electro-Pneumatic Inlet Valve Connection (Optional)...................................................................... 20
5.3 Filling Oil............................................................................................................................................................... 21
5.4 Cooling System Cover Removal......................................................................................................................... 22
5.5 Filling Cooling Liquid .......................................................................................................................................... 23
6 Electrical Connection ........................................................................................................................................... 24
6.1 Machine delivered with a Control Unit............................................................................................................. 25
6.2 Machine delivered with a Variable Speed Drive.............................................................................................. 26
6.3 Main Power Supply Connection ........................................................................................................................ 27
6.4 Modbus Control and Ethernet Settings (Optional) ......................................................................................... 28
6.5 Electrical Connection of the Cooling System ................................................................................................... 28
7 Commissioning ..................................................................................................................................................... 30
7.1 Description of User Interface Functions .......................................................................................................... 31
7.1.1 Roles and Users .................................................................................................................................... 32
7.1.2 Home...................................................................................................................................................... 33
7.1.3 Operations............................................................................................................................................. 35
7.1.4 Maintenance ......................................................................................................................................... 40
7.1.5 System.................................................................................................................................................... 40
7.2 Conveying Condensable Vapors........................................................................................................................ 44
8 Maintenance ......................................................................................................................................................... 45
8.1 Maintenance Schedule ....................................................................................................................................... 46
8.2 Oil Level Inspection............................................................................................................................................. 47
8.3 Cooling Liquid Level Inspection ........................................................................................................................ 47
8.4 Cleaning the Gas Ballast Filter (Optional) ........................................................................................................ 48

Table of Contents
Instruction Manual COBRA DX 0650-0950 A ACV_EN_en 3 | 64
8.5 Cleaning the Silencer (Optional)........................................................................................................................ 48
8.6 Oil Change............................................................................................................................................................ 49
8.7 Cooling Liquid Change ....................................................................................................................................... 52
9 Overhaul ................................................................................................................................................................ 54
10 Decommissioning ................................................................................................................................................. 55
10.1 Dismantling and Disposal .................................................................................................................................. 55
11 Troubleshooting ................................................................................................................................................... 56
12 Technical Data ...................................................................................................................................................... 58
13 Oil ........................................................................................................................................................................... 59
14 Cooling Liquid ....................................................................................................................................................... 60
15 EU Declaration of Conformity ............................................................................................................................. 61
16 UK Declaration of Conformity............................................................................................................................. 62

1 | Safety
4 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
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.
Always wear appropriate personal protective equipment in accordance with the local regulations.
The machine has been designed and manufactured in accordance with the state-of-the-art methods.
Nevertheless, residual risks may remain, as described in the following chapters and in accordance
with the chapter Intended Use [➔7].
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 trou-
ble-free operation.

Product Description | 2
Instruction Manual COBRA DX 0650-0950 A ACV_EN_en 5 | 64
2 Product Description
NOTE
Illustrations.
In this instruction manual, the machine illustrations are of the COBRA DX 0950 A. Although they differ from
the COBRA DX 0650 A, the principles and operation are similar.
VSD
VG
BF NP SI CD OUTMPPMR
CLD
ODP
TS1
INOSG EPIV
GBS GB
OSG CLD ODP CU
BGC, BGF, BGM, BGR, BGV
HMI ESS
NP
COM
LAN
VGPWS
CLF
CLV2
TB
CLV1TS2
AF
CLP
CLD
AHE
MP
MPS
OFP
PSP
Description
IN Suction connection (Inlet) OUT Discharge (Exhaust outlet)
AHE Air-water heat exchanger AF Axial fan
BF Base frame BGC Barrier gas connection – option*
BGF Barrier gas flow meter (FME) – option* BGM Barrier gas manometer (MAN) – option*

2 | Product Description
6 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
Description
BGR Barrier gas pressure regulator (PRV) – op-
tion*
BGV Solenoid valve (Barrier gas) – option*
CD Condensate drain COM Communication I/O port - option
CU Control unit CLD Cooling liquid drain plug
CLF Cooling liquid fill plug CLP Cooling liquid pump
CLV1 Cooling liquid vent valve (Heat exchanger) CLV2 Cooling liquid vent plug (Machine)
EPIV Electro-pneumatic inlet valve - option ESS Emergency stop switch
GB Gas ballast valve - option GBS Gas ballast silencer - option
HMI User interface (Human-machine) LAN LAN Communication port (Modbus TCP/IP) -
option
MP Magnetic plug MPS Main power switch - option
NP Nameplate ODP Oil drain plug
OFP Oil fill plug OSG Oil sight glass
PMR Plug for manual rotation of rotors PSP Pressure sensor plug
PWS Power supply (Cable gland) SI Silencer - option
TB Terminal box (Cooling system) TS1 Temperature switch (Machine)
TS2 Temperature switch (Cooling system) VG Ventilation grid
VSD Variable speed drive
* See Barrier Gas System Connection (Optional) [➔19]
NOTE
Technical term.
In this instruction manual, we consider that the term ‘machine’ refers to the ‘vacuum pump’.
NOTE
Illustrations.
In this instruction manual, the illustrations may differ from the appearance of the machine.
NOTE
Illustrations.
In this instruction manual, some maintenance illustrations are of the COBRA NX 0950 A. Although they are
slightly different from the COBRA DX 0650-0950 A, the principles are similar.

Product Description | 2
Instruction Manual COBRA DX 0650-0950 A ACV_EN_en 7 | 64
2.1 Operating Principle
The machine works on the one-stage, twin-screw pump principle.
Two screw rotors rotate inside the cylinder. The pumped medium is trapped between the cylinder
and screw chambers, compressed, and transported to the gas outlet. During the compression pro-
cess, the two screw rotors do not come into contact with each other or with the cylinder. There is no
need for a lubrication or an operating fluid in the compression chamber.
2.2 Intended Use
WARNING
In case of foreseeable misuse outside the intended use of the machine.
Risk of injuries!
Risk of damage to the machine!
Risk of damage to the environment!
●Make sure to follow all instructions described in this manual.
The machine is intended for the suction of air and other dry, non-aggressive, non-toxic and non-ex-
plosive 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 intended for indoor placement in a non-potentially explosive environment.
The machine is designed for indoor installations. For outdoor installations, consult your Busch repre-
sentative for special precautions.
The machine is capable of maintaining ultimate pressure, see Technical Data.
The machine is suitable for continuous operation.
Permitted environmental conditions, see Technical Data.
NOTICE
Chemical compatibility of the process gases with the machine component materials.
Risk of corrosion inside the compression chamber which can reduce performance and its life-
time!
●Check if the process gases are compatible with those following materials:
- Cast iron
- Steel
- Fluor elastomer (FKM/FPM)
●In doubt, please contact your Busch representative.

2 | Product Description
8 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
2.3 Standard Features
2.3.1 Air 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 air-water heat exchanger (AHE).
* T cooling liquid
Description
IN Suction connection (Inlet) OUT Discharge connection (Outlet)
AHE Air-water heat exchanger CLP Cooling liquid pump
CPL Coupling MOT1 Motor (Machine)
MOT2 Motor (Cooling liquid pump) MOT3 Motor (Air-water heat exchanger)
TS1 Temperature switch (Machine) TS2 Temperature switch (Cooling system)
VSD Variable Speed Drive
2.3.2 Temperature Switch
The temperature switch monitors the cooling water temperature of the machine.
The temperature switch has one switch point:
DX 0650 A Switch point T = 90°C. Trip, the machine must be stopped.
DX 0950 A Switch point T = 90°C. Trip, the machine must be stopped.
2.3.3 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.
Depending on the application, the sealing systems efficiency can be improved with a barrier gas sys-
tem, see Barrier Gas System [➔9].

Product Description | 2
Instruction Manual COBRA DX 0650-0950 A ACV_EN_en 9 | 64
2.4 Optional Accessories
2.4.1 Gas Ballast Valve
The gas ballast valve mixes the process gas with a limited quantity of ambient air to counteract the
condensation of vapor inside the machine.
The gas ballast valve has an influence on the ultimate pressure of the machine, see Technical Data.
2.4.2 Silencer
A silencer at the discharge connection (OUT) can be provided to reduce the exhaust gas noise.
●Interface DN 100 ISO-K
2.4.3 Barrier Gas System
The barrier gas system allows the supply of compressed air or nitrogen into the motor side shaft
seals to improve the sealing efficiency.
2.4.4 Electro-pneumatic Inlet Valve
CAUTION
Electro-pneumatic inlet valve pressure.
Risk of injuries!
Risk of damage to the machine!
●Busch recommends the installation of a pressure sensor with the following range and accuracy
values.
Pressure sensor range and accuracy
Range: 0-1000 mbar Accuracy: +/- 7.0 mbar
NOTE
To actuate the valve, compressed air or nitrogen must be supplied.
Default position of the valve: “normally closed”.
Connection size:
●DN100 ISO-K
The electro-pneumatic inlet valve is pilot operated and opens automatically when the machine starts
and closes when it stops.
The opening and closing of the valve can be delayed by the Warm-up & Cool-down* modes of the
machine (*Shutdown/Drying).

2 | Product Description
10 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
2.4.5 OTTO IoT Box
The machine can be equipped with the OTTO IoT Box.
It allows the vacuum pump to be connected to the Busch Cloud and collect live measured data
during its operation.
The IoT system consists in:
●The IoT Box
●A GSM antenna
●Sensors (Pressure sensor, resistance thermometer, vibration sensor)
For the activation and setup of this optional function, please contact your Busch representative.
For any additional information, refer to the specific document “OTTO IoT Box User's Manual, art. no.:
08702236702” or contact your Busch representative.
2.4.6 I/O and Communication Port
The control unit (CU) is equipped with a M12 I/O port and a RJ45 communication port (MODBUS) that
can allow remote control and monitoring of the machine.
Setup I/O port
Connector type: M12 12p female A coded (connection cable included in the scope of supply).
Power Supply
●24VDC power supply - Max 1.5A
Remote Pump Start
It allows the machine to be started by an external signal.
If pins 1 and 10 are bridged, the machine will start according to the settings of the HMI.

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Instruction Manual COBRA DX 0650-0950 A ACV_EN_en 11 | 64
NOTE
In case of a remote-control start, the machine must be integrated in the user's safety chain
(signal warning the user to stop the machine in case of problem or emergency stop).
NOTE
Standard factory setting: Bridge on terminals 24VDC / 24 inside the Control Unit (CU). Remove
the bridge and connect to Remote pump start.
Emergency Start
In case of HMI failure, bridge the 24VDC and number 34 terminals. The machine then operates at
100% speed and the inlet valve is open.
NOTE
No more settings are possible, but the safety chain and the dry contact remain functional.
External Safety Switch
It allows to add an external safety element.
Remove the bridge and put a dry contact instead.
NOTE
The bridge is mandatory in case of a remote-control use.
NOTE
Standard factory setting: Bridge on terminals 26 / 28 inside the Control Unit (CU). Remove the
bridge and connect to Remote safety contact.

2 | Product Description
12 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
External Contact (Pump Status)
●M12 connector Max 30VAC/DC 1.5A
●On terminal Max 250VAC/DC 10A
NOTE
System error, chain safety, EMO.
This contact gives information about the status of the machine and changes its status if an
event such as an error, a thermal fault or an emergency stop occurs.
●Status:
●Normal run: Pin 4-6 OFF / Pin 4-5 ON
●In case of error: Pin 4-6 ON / Pin 4-5 OFF
Vacuum Booster Control (Dry Contact)
●M12 connector: Max 30VAC/DC 1.5A
●On terminal: Max 250VAC/DC 10A
●Activation according to the settings of the HMI.
Modbus Control
Please refer to the chapter Modbus Control and Ethernet Settings (Optional) [➔28].

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Instruction Manual COBRA DX 0650-0950 A ACV_EN_en 13 | 64
2.4.7 Main Power Switch / Breaker
The machine can be equipped with a power switch to turn it on and off.
In case this power switch is not installed, an equivalent device must be installed in the customer's
system.
Customer power supply
2
1
3
4
8
5
6
7
Description
1 Power supply Standard Control Unit:
3L+PE 380-440V +/-10% (50/60Hz)
2 Power supply Optional Control Unit:
3L+PE 380-460V +/-10% (50/60Hz)
3 Wire gauge according to EN 60204-1 4 Must be provided by the customer
5 Lockable disconnect switch 6 Overload protection: C-curve - 80A
7 Vacuum pump terminal board (L1, L2,
L3, PE to the control unit)
8 The complete wiring diagram of the
control unit is placed inside the electri-
cal cabinet.
Cable gland size of the power input:
– M40 x 1.5 (cable Ø ► 20 … 33 mm)
2.4.8 Harting Connector
The standard version of the machine is equipped with a cable gland (PWS).
The machine can be equipped with a Harting connector (see Main Power Supply Connection [➔27]).

3 | Transport
14 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
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.
Transport with a forklift
The machine must always be handled with care, using either a forklift or a pallet jack. Handling ac-
cess must be from the underneath of the base frame (BF).
●Check the machine for transport damage.
If the machine is secured to a base plate:
●Remove the machine from the base plate.

Storage | 4
Instruction Manual COBRA DX 0650-0950 A ACV_EN_en 15 | 64
4 Storage
●Seal all apertures with adhesive tape or reuse provided caps.
NOTICE
Long storage time.
Risk of damage to the machine!
●Due to a long storage time the capacitors of the variable speed drive can lose efficiency because
of electrochemical processes. In the worst case, it can lead to a short-circuit and therefore to a
damage to the variable speed drive of the machine.
●Connect the machine every 18 months for 60 minutes to the mains.
If the machine is to be stored for more than 3 months:
●Wrap the machine in a corrosion inhibiting film.
●Store the machine indoors, in a dry and dust free environment and if possible, in original pack-
aging, preferably at temperatures between 5 ... 55 °C.

5 | Installation
16 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
5 Installation
5.1 Installation Conditions
NOTICE
Use of the machine outside of the permitted installation conditions.
Risk of premature failure!
Loss of efficiency!
●Make sure that the installation conditions are fully respected.
1
4
3
2
Description
1 ~120 cm 2 ~5 cm
3 ~50 cm 4 ~50 cm
●Make sure that the environment of the machine is not potentially explosive.
●Make sure that the ambient conditions comply with the Technical Data.
●Make sure that the environmental conditions comply with the protection class of the motor and
the electrical elements.
●Make sure that the installation space or location is vented such that sufficient cooling of the ma-
chine is provided.
●Make sure that cooling air inlets and outlets are not covered or obstructed and that the cooling
air flow is not affected adversely in any other way.
●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 deviation of 1° in any
direction is acceptable.
●Check the oil level, see Oil Level Inspection [➔47].
●Check the cooling liquid level, see Cooling Liquid Level Inspection [➔47].
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.

Installation | 5
Instruction Manual COBRA DX 0650-0950 A ACV_EN_en 17 | 64
5.2 Connecting Lines / Pipes
●Remove all protective covers before installation.
●Make sure that the connection lines cause no stress on the connections of the machine. There-
fore, we recommend installing flexible joints on the suction and discharge connections.
●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.
In case of long connection lines, it is advisable to use larger line sizes in order to avoid a loss of effi-
ciency. 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):
– Inlet filter: ISO-K DN100, DIN 28404
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.
●Make sure that the connection lines cause no stress on the connections of the machine. There-
fore, we recommend installing flexible joints on the suction and discharge connections.

5 | Installation
18 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
5.2.2 Discharge Connection
1 2
3
Description
1 Standard exhaust without silencer (SI) 2 Bottom view of the machine
3 Auxiliary port
NOTICE
Discharge gas flow obstructed.
Risk of damage to the machine!
●Make sure that the discharged gas will flow without obstruction. Do not shut off or throttle the
discharge line or use it as a pressurized air source.
Connection size(s):
– ISO-K DN100, DIN 28404
●Make sure that the connection lines cause no stress on the connections of the machine. There-
fore, we recommend installing flexible joints on the suction and discharge connections.
●Make sure that the counter pressure (also called “back pressure”) at the discharge connection
(OUT) does not exceed the maximum allowable discharge pressure, see Technical Data.

Installation | 5
Instruction Manual COBRA DX 0650-0950 A ACV_EN_en 19 | 64
5.2.3 Barrier Gas System Connection (Optional)
FME MAN BGC PRV
MV
Description
BGC Barrier gas connection FME Flow meter
MAN Manometer MV Solenoid valve
PRV Pressure regulating valve
●Connect the barrier gas connection (BGC) to the gas supply.
Connection size:
– G1/4, ISO 228-1
●Make sure that the gas complies with the following requirements:
Gas type Dry nitrogen or air
Gas temperature °C 0 ... 60
Maximum gas pressure bar (g) 13
Recommended pressure setting at the pres-
sure regulating valve (PRV)
bar (g) 3
Filtration µm 5
Recommended flow rate SLM (standard li-
ter per minute)
15 ... 20
Air quality (only for air) Acc. to ISO
8573-1
Class 5.4.4.

5 | Installation
20 | 64 Instruction Manual COBRA DX 0650-0950 A ACV_EN_en
5.2.4 Electro-Pneumatic Inlet Valve Connection (Optional)
1
2
Description
1 Electro-pneumatic inlet valve (EPIV) 2 Compressed air or nitrogen intake
Connection size:
●DN100 ISO-K
The electro-pneumatic inlet valve (EPIV) must be connected to compressed air or compressed nitro-
gen gas source.
●Make sure the gas complies with the following requirements:
Gas type Dry nitrogen or air
Gas temperature °C 0 … 50
Pressure setting for actuation bar (g) 1.5 … 8
Actuation mode Single acting actuator
Normally closed by lack of air