Hypertherm LR2075 - Manual (Page 30)

OPERATION
LR 2075 Laser Head Instruction Manual 4-5
Capacitive height sensor
The capacitive height sensor measures the relative capacitance between the cutting head’s nozzle and the workpiece.
The lower part of the cutting head is electronically excited and acts as a guard against any stray capacitance from other
sources including the moving components in the cutting head. The signal to the nozzle is carried by the center
conductor of the internal coaxial cable. The signal to the lower part of the cutting head is carried on the shield of the
internal coaxial cable.
Note: It is important that the lower part of the cutting head is not shorted to ground, and that there is
electrical isolation between the nozzle and the lower part of the cutting head. Isolation is
provided by the insulating washer and a ceramic coating on the top side of the nozzle adapter,
which prevents a false tip-touch error signal.
If a false tip-touch error is suspected:
Remove nozzle and retaining ring. Inspect for particles between parts, damage and cleanliness. Replace as necessary.
Note: The nozzle must be cool enough to touch with your bare hand before it is installed to avoid the
following condition:
If a nozzle hotter than 50° C (122° F) is installed on the cutting head, it will contract as it is
cooled by the nozzle adapter. This will result in a large frictional force between the nozzle and
adapter and will make it difficult to remove by hand. If this condition occurs, a pair of pliers may
be necessary to remove the nozzle.
Lower part of the cutting head
Nozzle
Retaining nut
Insulating washer
Nozzle adapter
Retaining nut wrench (104284)
O-ring
Contact pin