IMPULSE
®
•G+ & VG+ Series 4 Technical Manual
November 2020
Page 92
5.2.11 Load Float
When Load Float (C08-10) is enabled, it maintains the motor shaft at a stationary position with brake open. The Load
Float 2 (MFDI=35) function triggers the VFD to go into Load Float for the time set in C04-01. During Load Float, the
VFD will open the brake and hold the motor at a zero position. A FWD or REV run command will take priority over this
function. In NLB applications, the standard brake checks will be performed if starting from Base Block.
Table 5-27: Load Float Time 2 Parameter Settings
* Dependent on kVA (≤ 30 HP: 10; > 30 HP: 20)
5.2.12 Load Check II™
The Load Check II function is a load-limiting feature which ensures the programmed load limit of the hoist is not
exceeded. It prevents the lifting (and potential stall) of a load that is overweight. When IMPULSE
®
•G+ & VG+
Series 4 detects an overload condition it prevents any further lifting. The load may then be lowered at the speed
that is specified by the Load Check Alarm Speed (C05-08).
5.2.12.1 V/f Operation (A01-02 = 00)
When using Load Check II in V/f control method (during lifting) the IMPULSE
®
•G+ Series 4 will compare the motor
current readings (U01-03) to values stored during the Load Check set up process. If they exceed the values for the
active Load Check Zone, the IMPULSE
®
•G+ Series 4 will stop the motor based on the LC Alarm Action (C05-02)
and display a Load Check alarm (LC).
NOTE: If an application requires Load Check to be bypassed, an MFDI may be programmed to 69 (N.O.) or 6A
(N.C.)
NOTE: It is highly recommended to use OLV or FLV control methods for Load Check II.
5.2.12.2 OLV and FLV Operation (A01-02 = 02 and 03)
When using Load Check II in Open Loop Vector or Flux Vector control method, the IMPULSE
®
•G+ and VG+ Series
4 will compare the motor torque readings (U01-09) to values stored during the Load Check set up process. If they
exceed the values for the active Load Check Zone, the IMPULSE
®
•G+ and VG+ Series 4 will stop the motor based
on the LC Alarm Action (C05-02) and displays a Load Check alarm (LC).
NOTE: If an application requires Load Check to be bypassed, an MFDI may be programmed to 69 (N.O.) or 6A
(N.C.).
NOTE: The Load Check II function will alter the acceleration time, depending on loading. Therefore, it must be
disabled when using two or more hoists to lift a single load. Use MFDO H01-0x = 69 or MFDO H01-0x = 6A
to bypass Load Check.
Parameter Display Function Range Default
C04-01 Load Float Time2 Maximum duration of Load Float 2 time when
MFDI = 35
0–65535 sec 10
C04-02 Load Float Gain Gain for the control loop to hold the load from
moving during load float
0–100 10*
DANGER
Load Check II is designed to limit loads less than or equal to the crane’s rated capacity. Consult the factory and
crane manufacturer before calibrating Load Check II with a load heavier than the crane capacity.
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