Hypertherm XPR300 User Manual

Diagnostics and Troubleshooting
8
324 809480 Instruction Manual XPR300
Table 37 – Minimum and maximum ohmic resistance values for thermistors

At approximately 25ºC (77ºF), you can expect a resistance of
approximately 10,000 ohms.
d. If the resistance value is outside the minimum or maximum value in Table 37 on page 324,
contact your cutting machine supplier or regional Hypertherm Technical Service team. They
can help you to decide if there is a wiring fault or if thermistor replacement is necessary.
e. If the resistance value is at or very near 0 ohms:
 Inspect the wiring between each thermistor and its connector pins.
 Look for shorts between wires or to the ground.
f. If the resistance value is above 100 ohms and below the minimum:
 Remove the electrical power from the cutting system. Refer to Remove the power from
the cutting system on page 240.
 Allow the coolant to reach 85ºC (185ºF) or below.

It can take a long time for the coolant to reach 85ºC (185ºF) if the ambient
temperature is high. Contact your cutting machine supplier or regional
Hypertherm Technical Service team for guidance about how to cool the
cutting system, if necessary.
 Restore electrical power to the cutting system.
 Repeat step 8.
Thermistor temperature Minimum resistance (Ohms) Maximum resistance (Ohms)
25ºC (77ºF) 9,000 11,000
35ºC (95ºF) 5,000 7,000
45ºC (113ºF) 3,900 4,900
55ºC (131ºF) 2,500 3,500
65ºC (149ºF) 1,500 2,500
75ºC (167ºF) 1,000 2,000
85ºC (185ºF) 750 1,250
95ºC (203ºF) 600 1,000
105ºC (221ºF) 400 800
115ºC (239ºF) 300 600
125ºC (257ºF) 200 500
135ºC (275ºF) 150 400
145ºC (293ºF) 150 250
155ºC (311ºF) 125 225
165ºC (329ºF) 100 175

Hypertherm XPR300 Specifications

General

Brand	Hypertherm
Model	XPR300
Category	Welding System
Language	English