Published Document Number: BICWUT01
• Specified Date: 20050118
• As-of Date: 20050118
• Access Date: 20050118
• Depth: detail
• Applicability: CWU
• Language Code: ENG01, Purpose: publication, Format: 1colA
Document—
Troubleshooting Basket
Speed Errors on Single-
motor Washer-
extractors
PELLERIN MILNOR CORPORATION POST OFFICE BOX 400, KENNER, LOUISIANA 70063 - 0400, U.S.A.
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BICWUT01 (Published) Book specs- Dates: 20050118 / 20050118 / 20050118 Lang: ENG01 Applic: CWU
Troubleshooting Basket Speed Errors on Single-motor Washer-
extractors
This document describes the proper procedure for troubleshooting errors related to basket motor
speed on machines equipped with a single motor, an inverter, and a digital-to-analog (D-to-A)
board.
1. As the basket rotates, a photoeye sees each spoke of the main drive pulley. The photoeye
sends a pulse representing each pulley spoke to an input/output board (I/O #1).
2. I/O #1 determines the time between pulses and communicates this to the machine processor
board.
3. The processor board calculate the RPM and compares this value to the digital value
corresponding to the programmed basket speed. If the speed is incorrect, the processor board
signals the digital-to-analog (D-to-A) board to slightly increase or decrease the basket speed.
4. The D-to-A board converts the digital signal from the processor board to an analog voltage of
0 to 10 volts and sends it to the inverter. The speed at which the inverter drives the motor is
directly related to the voltage output of the D-to-A board.
5. The inverter interprets the voltage from the D-to-A board and adjusts the voltage and
frequency of the motor supply to drive the motor at a different speed.
6. The motor speed changes, causing the spokes on the main pulley to pass the photoeye at a
different rate, and the speed control circuit is complete.
The most common indicator of a problem somewhere in the speed control circuit is that the
basket does not turn at the desired speed, or does not turn at all. The chart in Figure 1
describes the overview of the troubleshooting process.
WARNING 1 : Electrocution and Electrical Burn Hazards—Hazardous voltages can
cause sever injury or death.
• Whenever possible, lock all power sources feeding the inverter in the “OFF” position.
• The status indicator LEDs and the inverter display will be extinguished when the DC
voltage inside the inverter is below 50VDC. Wait at least one additional minute for
voltages to further dissipate.
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Troubleshooting Basket Speed Errors on Single-motor Washer-extractors
Figure 1: Troubleshooting Speed Errors
Process Chart
Legend
Y.
N.
1.
Yes
No
Machine does not run at desired speed.
2.
A.
3.
B.
4.
C.
5.
D.
6.
E.
7.
F.
8.
G.
9.
Section 1: Is desired speed programmed in wash formula?
Edit wash formula.
Section 2: Are inverter parameters correct for this machine model?
Contact Milnor, and correct inverter parameters.
Section 3: Does digital counts value match desired speed?
Contact Milnor for updated software.
Section 4: Does D-to-A output voltage at D-to-A board match desired speed?
Replace D-to-A board.
Section 4: Does D-to-A voltage at inverter match desired speed?
Check wiring from D-to-A board to inverter.
Section 5.1: Does inverter output frequency match input voltage?
Review inverter parameters, and contact Milnor Customer Service.
Section 5.2: Is inverter output amperage within normal limits?
Contact Milnor Customer Service before repairing or replacing inverter.
Section 6: Does motor test within normal limits?
Contact Milnor Customer Service before repairing or replacing motor.
.
H.
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1. Verify Programmed Speed
Verify that the machine is programmed correctly. The desired basket speed is programmed on the
second page of each wash formula step.
Display or Action
Explanation
Insert the programming key into the Run/Program keyswitch
and turn the key 1/4 turn to the right. This accesses the Program
Menu.
P
Program Menu item 0 indicates that it is safe to turn the key to
the Run position. If you make any changes to a wash formula or
machine configuration, do not turn the key to the Run position
unless this menu item is displayed.
PROGRAM 0 MENU
OK TURN KEY TO RUN
Press the up and down arrow keys to select other items from the
Program Menu.
^
Display or Action
Explanation
Select Program Menu item 1 to view the programmed steps in
PROGRAM 1 MENU
the wash formula.
ADD/CHANGE FORMULA
Press Enter/Next to confirm your selection and prompt for the
desired wash formula number,
u
or
press Cancel/Escape to return to Program Menu item 0.
c
Display or Action
Explanation
This display prompts for the number of the formula in which the
error occurs. If the error appears in several formulas, only one
needs to be verified.
ADD/CHANGE FORMULA
00
Enter the formula number. An incorrect formula number can be
changed at the next display.
,
0 1
The cursor flashes on “CHANGE” and the first digit of the
number for any existing formula. “ADD” flashes if the formula
does not exist, prompting you to program a new formula.
ADD/CHANGE FORMULA
01 FORMULA 01
If the selected formula is not correct, enter another formula
number at this display.
Confirms the selected formula and advances to the next display.
The cursor flashes on the first character of the name for step 01.
u
u
F01 FORMULA 01
S01 00 STEP 01
Accepts the formula name and advances to the overview display
for step 01.
The overview display for step 01. Notice that there is no cursor
flashing.
F01 TMMQFFFHC3WLL S
S01 2050150133110 0
Advances to the step decisions for step 01.
u
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Troubleshooting Basket Speed Errors on Single-motor Washer-extractors
Display or Action
Explanation
The first page of step decisions includes the type and duration of
the step, the desired temperature, water valves, fill action, bath
level, and steam code.
F01 TMMQFFFHC3WLL S
S01 2050150133110 0
Press
decisions.
several times to advance to the second page of
u
u
The second page of step decisions includes the prompt for the
desired basket speed. If the value shown here is not the desired
value, change it. The complete procedure for programming a
wash formula is described in the reference manual for your
machine.
F01 CCNNWSSS*RPMDRC
S01 000000000-30000
2. Verify Inverter Parameters
The machine processor board adjusts the speed of the motor by communicating with the inverter.
The inverter contains several values, called constants or parameters, that control how the inverter
interprets signals from the machine processor. These parameters were programmed into original
equipment inverters at the Milnor factory before the machine was shipped, but replacement
inverters must be programmed with the correct constants for machine type, inverter type, and
voltage. If these parameters are incorrect, the inverter will not work as expected.
The procedure for verifying the inverter parameters varies among inverters, but is described in
detail in the documentation provided by the inverter manufacturer. Replacement manuals for
Inverter constants for specific inverters and Milnor machine models are available in the Customer
3. Verify Digital Value of Programmed Speed
If the desired value is correctly programmed, view the speed diagnostics to verify that the
machine controller is commanding the programmed speed. The machine must be running a step
in which the speed is wrong.
Supplement 1
Creating a Test Formula
When a wash step begins, the beginning value sent to the inverter is calculated according to this
equation:
V0 = [RPMd * (C/RPM)] + D
Where:
V0 = beginning value sent to inverter
RPMd = Desired basket speed in RPMs
C/RPM = Counts per RPM
D = Offset
If all motors, inverters, and digital-to-analog boards could be manufactured to exactly the same
specifications, adjustment of the basket speed would not be necessary. However, manufacturing
tolerances allow minor variances in these components, so a feedback system is used to monitor
the basket speed and make adjustments to achieve the desired value.
If a speed adjustment is required during a wash step, the machine controller signals the inverter
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to increase the basket speed by two RPMs or decrease the speed by one RPM at each
adjustment. These adjustments are made three seconds before the end of the programmed
basket On time (programming decision XXX). Because the speed is adjusted only one time per
On time period, formulas programmed with On times near the maximum may require several
minutes to achieve the programmed speed.
To give the machine sufficient time to achieve a steady speed state and to maintain that speed
during troubleshooting, it is often a good idea to program a special test formula. To
troubleshoot a speed error in a bath step, the test formula should contain a bath of moderate to
long duration with relatively brief basket On and Off times.
1. For step 01, set the Type of Step to a Wash with basket rotation (T = 1 or 2).
2. Set the Step Time to about 10 minutes (MMQ = 100).
3. Do not set a temperature (FFF or CCC = 000).
4. Program the machine to fill with cold water (C = 1) to a low level (LL = 04).
5. Program no chemical injection (CC = 00).
6. Program the speed in RPMs (e.g., RPM = 018) that is used in the erroneous production
formula.
7. Program the basket On time to 20 seconds (XXX = 020) and the basket Off time to 3
seconds (YYY = 003).
8. End the formula (E = 0).
Use the formula created in Supplement 1 or a similar formula to evaluate other possible sources
of the problem.
Display or Action
Explanation
With a step running in which the problem occurs, press this key
to view the speed diagnostics data. Press this key a second time
to close the speed diagnostics and display the normal run data.
6
The top line of the speed diagnostics display is the same as when
the formula is running normally. All speed diagnostics are
contained on the second line.
10:38 F0005S03 02:37
0195 RPM=A029/D030
The leftmost number is the calculated digital counts value. You
can determine the initial digital count for the programmed basket
speed from Table 1 and the equation below:
Cd = [RPMd * (C/RPM)] + D
Where:
Cd = Desired digital counts value
RPMd = Desired basket speed in revolutions per minute
C/RPM = Counts per RPM
D = Offset value
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Troubleshooting Basket Speed Errors on Single-motor Washer-extractors
Table 1: Model-Specific Data
Maximum
Frequency
Maximum
Wash RPM
Counts per RPM
(C/RPM)
Machine Model
30022F_W
30022X_W
36030F_S
Offset (D)
155
40
43
186
205
155
178
195
36030F_W
42026V_W
42032F_S
5
15
40
42032F_W
48040F_W
68036F_N
38
32
6
7
170
Important: Values shown are subject to change without notice. Contact Milnor
Customer Service for verification.
Note 1: The counts and offset values are configurable in controller software WUWESME, used in single-
motor E-style and divided cylinder washer-extractors. Contact your dealer or the Milnor service department
for assistance with these machines.
Display or Action
Explanation
The rightmost number of the bottom line indicates the desired
(programmed) basket speed for this step. This value matches the
value programmed in the wash formula.
10:38 F0005S03 02:37
0195 RPM=A029/D030
The middle number of the bottom line indicates the current
calculated basket speed. Input/output board #1 determines the
time between each main pulley spoke passing the photoeye and
reports this data to the processor board at each communication
cycle, which is usually more often than once per second. The
processor board filters the raw data from the input/output board
and displays the most recent valid value.
10:38 F0005S03 02:37
0195 RPM=A029/D030
Tip: Large variations in the achieved RPM value are possible early in extract steps because the valid
range includes values from 0 RPMs to the maximum extract RPM of the machine. These
variations have no effect on how the machine operates because of the frequency with which new
data is reported.
4. Verify Output Voltage of D-to-A Board
If the microprocessor is displaying the correct calculated digital value, the next step is to verify
that the digital-to-analog board is putting out the appropriate signal voltage.
1. Calculate the voltage of the signal that the D-to-A board should deliver to the inverter:
Vd = Cd / 409.5
Where:
Vd = Desired voltage
Cd = Desired counts per RPM
For example, assume the machine is configured as a 48040F_W and the desired wash speed
is 24 RPMs.
a. From Table 1, we see that this machine model makes six counts per revolution and has an
offset of 15.
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b. Calculate the desired counts for a basket speed of 24 RPMs:
Cd = [RPMd * (C/RPM)] + D
Cd = [24 RPMs * (6 counts per RPM)] + 15
159 = 144 + 15
c. Calculate the desired voltage:
Vd = Cd / 409.5
0.3883 = 159 / 409.5
2. The DC voltage measured at the output terminals of the D-to-A board and at analog voltage
input terminals FV and FC on the inverter (shown in Figure 2) should match this number.
You may see a small voltage drop from the D-to-A board to the inverter.
Figure 2: Measuring Control Voltage at D-to-A Board and Inverter
Digital-to-Analog Board
Legend
A.
B.
C.
D.
E.
F.
MTA-43 Pin 3
MTA-43 Pin 8
Inverter terminal A1
Inverter terminal AC
Inverter terminal FV
Inverter terminal FC
Inverter Analog Terminals for Yaskawa F7
Inverter Analog Terminals for Yaskawa GPD 506
.
3. If this value is wrong at the D-to-A board, replace the board.
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Troubleshooting Basket Speed Errors on Single-motor Washer-extractors
4. If the value is correct at the D-to-A board but wrong at the inverter, check the wiring between
the board and the inverter.
5. If the value is correct at both sets of terminals, troubleshoot the inverter.
5. Troubleshooting the Inverter
5.1. Verify Inverter Output Frequency—Use the inverter keypad to display the current
desired frequency. This frequency should correspond to the input voltage according to this
equation:
Fd = (Vout / 10) * Fmax
Where:
Fd = Desired frequency
Vout = DC voltage output from D-to-A board
F
max = Maximum inverter frequency (see Table 1)
When the machine is running normally, the inverter display appears similar to one of the
illustrations in Figure 3.
Figure 3: Typical Inverter Run Displays
Yaskawa GPD 506 Model
Yaskawa F7 Model
Legend
A.
B.
C.
Desired frequency
Actual frequency
Actual amps
The specific procedure for viewing the inverter operating parameters varies among inverter
models.
• For Yaskawa F7 models, the actual and desired frequencies and the actual amperage are
visible on the normal operating display.
• For Yaskawa GPD 505 and 506 models, press the DSPL button on the inverter once to
advance from the Desired Frequency display to the Actual Frequency display.
5.2. Verify Inverter Output Amperage—Verify the current being delivered to the motor.
Contact the Milnor® Customer Service department for guidelines on the acceptable amperage for
the conditions.
For Yaskawa GPD 505 and 506 models, press the DSPL button on the inverter once to advance
from the Actual Frequency display to the Actual Amperage display.
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6. Testing the Motor
If the procedures described earlier in this document do not eliminate the error, have the motor
tested by a reputable facility.
— End of BICWUT01 —
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