Belt Speed Calibration --- Open Loop - Blodgett MT3255 Series Service And Repair Manual

MT3255 and MT3270

BELT SPEED CALIBRATION --- OPEN LOOP

NOTE: The following procedures must be per-
formed after dc voltage levels have been
set and are known to be accurate.
The cooking time digital display should be ad-
justed when changing any of the system compo-
nents. Prior to adjusting the display, determine the
following two specifications:
1. The number of pulses per spindle revolu-
tion generated by the Hall effect pickup.
Move the plastic end-caps on the pickup lo-
cated on the DC motor. If the pickup is marked
with the number 2, it is a single pulse per revo-
lution pickup. If the pickup is marked with the
number 10 (Standard After 6-1-91) it is a five
pulse per revolution pickup. Replace the end-
caps. Refer to page 5---1 for pickup trouble-
shooting.
2. The manufacturer and the voltage rating of
the DC drive motor.
This information is embossed on the name-
plate located on the motor's case.
Once the above specifications have been deter-
mined, perform the following calibration proce-
dures.
1. Remove the screws securing the cooking time
display lens cover. Remove the lens cover. If a
5 pulse pickup is used, verify that the multiplier
potentiometer is set to the x10 position (refer
to FIGURE 5 for the potentiometer location).
Belt speed DIP switch located
behind cooking time digital display
Cooking Time
INCREASE
X10
Multiplier potentiometer located behind
cooking time digital display
For 5 pulse pickups set to x10
X1
FIGURE 5
DECREASE
4---5
Set The Belt Speed DIP Switches.
Set the DIP switches using the data from the table
below.
Pickup DIP Switch Setting
MT3255 -- 60 Hz Motors
Single 7, 6, 5, 4, 3 ,2 , 1 --- set to OFF
5 Pulse 7 --- set to OFF
MT3270 -- 60 Hz Motors
Single 8, 6, 2 --- set to OFF
5 Pulse 7, 5, 1 --- set to OFF
MT3255 -- 50 Hz Motors
Single 8, 5, 3, 2 --- set to OFF
5 Pulse 7, 4, 2, 1 --- set to OFF
MT3270 -- 50 Hz Motors
Single 8, 6, 5, 4, 3, 2, 1 --- set to OFF
5 Pulse 7, 5, 4, 3, 2, 1 --- set to OFF
TABLE 2
Rear Of
Control
8 7
OFF
128 64 32
FIGURE 6
Switch Number
6 5 4 3 2 1
16 8 4 2 1
Switch Value