ThyssenKrupp Flow2 User Manual

2007.03.07Flow2 stairliftTab 06: Systematic fault finding
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Systematic fault finding
- your nose (a smell of burning on a printed circuit board)
- your fingers (play in the system).
The example of the lamp switching
Suppose that you’ve removed the bulb from the fitting. You now measure the resistance of the wires
to the fitting by measuring directly across the terminals of the switch. You measure 2 Ohms.
Consequently, you conclude that there’s a short-circuit in the wiring. Wrong! The switch is switched
on, and consequently you also measure the resistance of the transformer winding. You can measure
the resistance of the wiring properly only by disconnecting the wires from the transformer.
The example of the lamp switching
A fault tree could be as follows:
CAUTION
Make sure you know what you’re measuring!
TIP
Make a note of all your findings, and draw a fault tree. Use these to keep a record of the
causes you have been able to eliminate. You can use numbers to indicate the sequence
in which you work.
Lamp does not light
2. Lamp broken 3. No voltage at fitting 1. Lamp not properly
screwed into fitting
4. Dirty fitting
4. Switch defective1. No voltage at the trans-
formator
2. Loose contact in the wir-
ing to the lamp
3. Short circuit in the wiring
to the lamp
3. Short circuit in the wiring
to the transformer
2. Loose contact in the wir-
ing to the transformer
1. No voltage at the wall
socket
4. Transformer defective
Fig. 2-3 Example fault tree

ThyssenKrupp Flow2 Specifications

General

Brand	ThyssenKrupp
Model	Flow2
Category	Stairlifts
Language	English