3
Instructional Booklet
IB013003EN
Effective June 2023
Instructions for installation, operation,
and maintenance of Magnum MR2
(integral racking)
EATON
www.eaton.com
Motorized remote racking (MR2)
Magnum PXR or Power Defense SB (PD-SB) drawout breakers
with the MR2 integral racking option allow an operator to remotely
rack a Magnum breaker from a distance of 30 feet (9 .14 m) or
greater depending on the communication option installed . The
MR2 helps to mitigate electrical arc flash exposure by allowing the
operator to work from outside the arc flash boundary . The integral
racking system consists of a breaker with integral motorized racking
assembly, wired cassette, controller, and a customer provided user
interface (see Figure 1) . The racking assembly contains safety
and component position sensing features located on the racking
mechanism of the breaker . The controller accepts 120 Vac and
supplies power to a motor based on the user input . The position
of the Magnum breaker is detected by three limit switches located
internal to the racking mechanism . Circuit breakers equipped with
MR2 have a layer of Magnalube applied to primary disconnects . For
additional lubrication information, refer to Appendix or “Section 7:
Importance of Maintenance” in MN013016EN .
Control power requirements:
•
Input voltage, nominal: 120 Vac; 10 A,
•
Input voltage range: ±10% nominal .
The MR2 integral racking system is shown below (see Figure 1) .
Breakers equipped with MR2 can be identified by the blue colored
levering fascia . The user can control the system by means of a
pendant, Modbus master (such as the Eaton Power Distribution
Monitoring and Control system), or separately wired I/O buttons .
Controller can be mounted to the left side (preferred) or right side of
the cassette . If placed in other areas of the switchgear, extension
wires can be added with the existing terminal blocks . The eight
MR2 tertiary wires connect the controller to the MR2 levering
device thru the breaker/cassette secondary connectors . The wire
description is as follows:
Grey
= Racking position switch – Common;
Green = Racking position switch – Disconnect;
Yellow = Racking position switch – Test;
Red
= Racking position switch – Connect;
Blue
= Permissive switch circuit;
Blue
= Permissive switch circuit;
Black
= Motor DC (+);
White
= Motor DC (-) .
Customer will need to supply the 120 Vac input to the controller .
Figure 1. MR2 integral racking system.
Secondary connectors
The MR2 wired connections (tertiaries) pass through the breaker
and cassette’s secondary connectors . The eight tertiary contacts are
connected when the breaker is placed in the disconnect position and
remain connected through test and connect (see Figure 2) .
Figure 2. Breaker in disconnect position.
Pushing on the top of the breaker cover (see Figure 3) will ensure
good electrical connection of the tertiary contacts in the disconnect
position .
Figure 3. Tertiary connection in disconnect.
The eight MR2 tertiary contacts are located in the middle of the
secondary connectors . The breaker side and cassette side are
shown in Figure 4 and Figure 5 .
Figure 4. Breaker side secondary connector.
Figure 5. Cassette side secondary connector.
Circuit
breaker
side view
MR2 tertiaries
Rear of
compartment
Primary
connections
not made
Compartment
front door
