Description
This error monitors the treadmills
power bit reading when the treadmill was operating at speeds
of 1 mile per hour or less. Power
bits indicate the relative time that the motor controller drive circuit
is turned on. Therefore power bits
is an indication of the amount of power the load is
demanding from the motor controller.
Error 20 indicates that at a speed of 1 mile per hour or less
an excessive amount of power is
being demanded from the motor controller for an excessive
period of time.
Possible
Causes
1. The treadmill user (especially a
heavier user) is standing on the drive belt as they start the
running belt into motion. Starting
the running belt into a very heavy load can cause the error
20 condition.
2. The running bed and/or running
belt is badly worn and the error 20 occurs when the user
steps onto the running belt.
3. The drive motor brushes are badly
worn and not making sufficient contact with the drive
motor commutator. The error 20
occurs when the user steps onto the running belt. The
treadmill may also bog down when the
user steps onto the running belt.
4. On treadmills utilizing an SCR
motor controller, a leaky or shorted drive motor filter capacitor
could raise the current demand
sufficiently to cause the error 20.
5. On treadmills utilizing an SCR
motor controller, a leaky or shorted drive motor inductor could
raise the current demand sufficiently
to cause the error 20.
6. A shorted or de-magnetized drive
motor is causing the high power demand.
Possible
Remedies
1. The user should be instructed to
straddle the running belt and start the treadmill at a low
speed (1 mile per hour or less) and
then step onto the running belt.
2. A clamp-on A.C. ammeter must be
used to determine the amount of A.C input current being
drawn by the treadmill under no load
and loaded conditions. The current readings can be
used to determine the condition of
the running belt and/or running bed. These same readings
should be taken on a similar unit
with a known good running belt and running bed. Those
readings can then be used as a
benchmark for future use. Replace the running belt and/or
running bed as required. Remember,
many running beds are double sided and the bed can
be flipped over rather than being
replaced.
3. Replace both drive motor brushes.
4. A clamp-on ammeter should be used
to measure the A.C. input current at no load. The filter
capacitor should then be electrically
isolated from the drive motor circuit. The drive motor
leads must be kept intact so that
the drive motor will operate with the filter capacitor removed
from the circuit. The no load A.C.
input current should be measured again, if the A.C. input
current is significantly lower,
replace the filter capacitor.
5. Use the same procedure as in step
4 above, except remove and isolate the inductor from the
drive motor circuit instead of the
filter capacitor.
6.
A known good drive motor must be substituted for the existing drive motor.