Harrington Hoists and Cranes MR Trolley - (MR2) - Manual (Page 23)

Figure 3-13 Optional trolley installation method – 8 Ton and Larger
3.4 Electrical Connections
3.4.1

Ensure that the voltage of the electric power supply is proper for the hoist or trolley.
3.4.2

Do NOT apply electronic soft-start control or voltage varying controls to the MR2
trolley. Use of such devices may cause the motor brake and other electrical components to
malfunction. Variable frequency drives MAY be used with single speed MR2 trolleys, contact
Harrington Hoists, Inc. for more information.
3.4.3

Before proceeding, ensure that the electrical supply for the hoist or trolley has
been de-energized (disconnected). Lock out and tag out in accordance with ANSI Z244.1 “Personnel
Protection -Lockout/Tagout of Energy Sources”.
3.4.4

To avoid a shock hazard, DO NOT perform ANY mechanical or electrical
maintenance on the dual speed (or VFD control) trolley or hoist within 5 minutes of de-energizing
(disconnecting) the trolley or hoist. This time allows the internal VFD capacitor to safely discharge.
3.4.5

Do Not remove power to the dual speed (or VFD control) hoist or trolley during
operation.
3.4.6

All dual speed trolleys are equiped with a VFD. The VFD is used to control the
high and low traversing speeds and accelereations. These speeds and accelerations come preset
from the factory, 80/13 feet per minute. Speed (frequency) and acceleration/deceleration time
parameters can be customized. Refer to Section 3.5.10 for trolley specific speed ranges and
instructions and Section 3.5.11 for trolley specific acceleration/deceleration ranges and instructions.
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