R&M Materials Handling HOIST MONITORS - Manual (Page 28)

R&M Materials Handling, Inc.
4501 Gateway Boulevard
Springfield, Ohio 45502
P.: (937) 328-5100
FAX: (937) 325-5319
28/105
R&M Materials Handling, Inc. reserves the right to alter or amend the above information without notice.
5.6 Starting and stopping through slow speed (2 speed application only)
Starting the motor directly in high speed will cause a high starting current that heats up the motor quite
rapidly. To prevent the motor from overheating, the hoist-monitoring unit will always start the motion in
slow speed. After a short period of time, the hoist-monitoring unit allows driving in fast speed when
requested.
Stopping the motion directly from high speed will cause excessive brake wear. To protect the brake lining
material, the hoist-monitoring unit will initiate slow speed for a brief moment, before the mechanical brake
is closed.
This function can only be activated in two-speed systems
A. Speed
B. Position of pushbutton (0, 1, 2)
5.6.1 Starting and stopping through slow speed instructions
Starting and stopping through slow speed parameters
Param. Value Description Note
4-7Load param Load calculation menu Accessible with password 4: 8124
4-7-13 0.20s Acceleration time from stop to slow speed 0.00s – 1.00s See description below
4-7-14 0.30s Acceleration time from slow speed to fast speed 0.00s – 1.00s See description below
The parameters 4-7-13 and 4-7-14 have the following functions:
•
During acceleration from zero to slow speed and deceleration from slow speed to zero, the unit will
not calculate or supervise the overload protection and current measurement for a period of time
determined by parameter 4-7-13.
• During acceleration from slow speed to fast speed and deceleration from fast speed to slow speed,
the unit will not calculate or supervise the overload protection and current measurement for a period
of time determined by parameter 4-7-14.
• The above function prevents the overload from tripping during the acceleration and deceleration
moment, especially in two-step systems with motor-torque calculation based overload protection,
since the starting currents are momentarily quite high.
• When accelerating from zero directly to fast speed, the motion starts in slow speed for a period
determined by par. 4-7-13.
• When decelerating from fast speed to slow speed, the unit will keep the fast speed active for a period
determined by par. 4-7-14.
• When decelerating from fast speed directly to zero, the unit will activate the slow speed for a fixed
period of 250ms (not adjustable by parameters!).
The above function prevents the use called as “inching”, “jogging” or “tipping” operation.
Once the slow speed output is activated, it remains active for 250ms, even if the input command
drops off within this time. This prevents the directional contactors to drop off during the high starting
currents.