Hypertherm ArcGlide Torch Height Control Instruction Manual page 98

INStALLAtIoN
ArcGlide setup parameters (continued)
Maximum Speed
Description: This parameter sets the maximum linear speed that the THC can achieve.
This value depends on the lifter motor speed at 45 VDC, the screw pitch, the weight of the lifter load,
and the desired speed of operation. This value is used as the 100% speed value when scaling the
control equations. It is important that this value is set correctly because it affects the scaling of all the
other control loops.
When to use: During installation. Set this parameter before optimizing Speed Gain.
How to use: Set this value to a speed that can be achieved easily. Use a conservative setting assuming low
incoming AC line voltage. If this speed is set too high, the maximum available motor drive voltage will
be insufficient to drive the motor to the desired maximum speed. This will make the top of the linear
control range unavailable and result in sub-optimal operation. If the Maximum Speed is set too high, it
may be difficult for the THC to operate precisely at slow speeds when trying to control the arc voltage
or position to an accurate IHS distance. If this speed is set too low, the linear control range will only
cover the low portion of the available mechanics range and the result will be sub-optimal.
For the Hypertherm 24.13-cm (9.5-inch) lifter, this value is 0.1524 centimeters (600 inches) per
minute. At the low input line voltage limit, the motor drive is capable of supplying about 45 VDC. The
motor used in the Hypertherm 24.13-cm (9.5-inch) lifter will produce full rated torque at about 3,300
RPM driven by this voltage. The Hypertherm 24.13-cm (9.5-inch) lifter has a 5mm pitch ball-screw
which requires 25.4 (in/mm) / 5 (mm) = 5.08 revolutions to travel one linear inch. This results in a
value of 3,300 (RPM) / 5.08 (revolutions/inch) = 650 linear inches per minute (IPM) of travel speed.
This value was rounded down to the nearest even hundreds to guarantee a 100% value under all
conditions.
Example: 600 IPM
fast Speed
Description: This speed is used for all automatic rapid moves such as the End-of-Cut-Retract or the Initial
Approach to the workpiece.
When to use: During installation.
How to use: This parameter is usually set equal to the value of Maximum Speed but it can be set lower if there is a
heavy load on the lifter.
With the Hypertherm 24.13-cm (9.5-inch) lifter this value is set to 600 IPM.
Example: 600 IPM
Slow Speed
Description: This speed is the Homing Speed and is the fastest speed used for manual moves. It is also the
maximum speed limit used during arc voltage control.
When to use: During installation
How to use: With the Hypertherm 24.13-cm (9.5-inch) lifter this value is set to 150 IPM.
Example: 150 IPM
2-62 ArcGlide THC Instruction Manual