SECTION 3—SAFETY INSPECTION/TROUBLESHOOTING
31
Field Load Test
NOTE: For this procedure, refer to FIGURE 3.1.
• Old batteries lose their ability to store and release power, due to increased internal resistance. This means that as you try
to take power from the battery, some of that power is used up in the process of passing through the battery, resulting in
less voltage at the posts. The more power drawn, the lower the voltage available. When this lost voltage drops the output
1.25 volts under load (2.5 for a pair), replace the batteries.
• To spot this problem, test the batteries under load.
• Use a digital voltmeter to check battery charge level at the charger connector. It is located on the joystick. If reading is 2.5
volts or more for a pair, the batteries must be charged.
NOTE: Read these instructions carefully and the manufacturer’s instructions on the digital voltmeter before using the digital voltmeter.
NOTE: Invacare recommends that only a qualified technician perform this test.
1.
Ensure that power is Off.
2.
Make sure battery is fully charged. An extremely discharged battery will exhibit the same symptoms as a bad one.
3.
Remove the footrests from the wheelchair. Refer to user manual shipped with wheelchair.
4.
Connect the voltmeter leads to the charger port on the wheelchair as shown in FIGURE 3.1.
NOTE: Most digital voltmeters are not affected by polarity, however, analog meters (meters with swinging needles) can be and should
be used carefully. A good meter reading should be 25.0 to 26 VDC.
NOTE: When performing STEPS 5 and 6 ensure feet are clear from casters and stationary object - otherwise injury may result.
5.
Sit in wheelchair and place feet against a door jam, workbench or other stationary object.
6.
Turn the power On and carefully push the joystick
forward, trying to drive the wheelchair through the
stationary object.
NOTE: This puts a heavy load on the batteries as they try to push
through the stationary object. If the wheels spin, have two
individuals (one on each arm) apply as much downward pressure
as possible on the arms of the wheelchair.
7.
Read the meter while the motors are straining, no
longer than 3-4 seconds, to determine the voltage under
load.
NOTE: If the voltage drops more than 2.5 volts from a pair of fully
charged batteries while under load, they should be replaced
regardless of the unloaded voltages. Refer to Replacing Batteries
on page 65.
Motor Testing
NOTE: For this procedure, refer to FIGURE 3.2.
1.
On the 4-pin motor connector, locate the two contacts in
the motor connector housings.
2.
Set the digital multimeter to measure resistance in
ohms (
Ω
).
3.
Measure the resistance between the two motor contacts.
NOTE: A normal reading is between .5 to 5 ohms. A reading of
O.L. (open line) or in excess of 15 ohms indicates a problem. High
readings are generally caused by bad connections and/or damaged
brushes. Contact Invacare.
FIGURE 3.1
FIGURE 3.2
Charger Port
Digital Voltmeter
4 Pin Motor
Connector
Motor
Cap
