Putzmeister Telebelts give the operator the means to adjust the speeds of the main and feeder conveyors. When adjustments are made to the belt speed knobs (potentiometers), a variable signal (4 to 10 mA) is sent to the 14A20 amplifiers. Depending on the input signal, these amplifiers supply 0 to 10 volts to the belt on/off relays, then to the 14A24 proportional amplifiers, known as belt cards.
The belt cards supply voltage to the motor control valves 14B36. Feedback sensors on the motor control valves report valve position back to the belt cards.
Note: Older Telebelts have the belt circuits on schematic page 10. The components are 10Axx, instead of 14Axx.
All of the components in the belt card circuits operate on 24 volts. The 12/24 converter is on the inside of the cabinet door. The belt cards are protected by 24v fuses. All 24v conductors are purple.
There are two completely separate circuits (refer to A370160K, pages 6 and 14 shown here):
Main belt: A43.1, 14A20.1, 6K360, 14A24.1, 14B36.1
Feeder belt: A43.2, 14A20.2, 6K361, 14A24.2, 14B36.2
Older TB-105’s using schematic A383009 have the same components on pages 6 and 10. The component numbers are 10A20.1,2, 10A24.1,2 and 10B36.1,2
The belt cards have indicator LED’s and adjustment screws as shown.
Belt card adjustment may be required for component wear or replacement. If the belt cards were swapped for troubleshooting, and not put back where they came from, adjustments could be off.
ADJUSTING CARD SETTINGS
The following outlines the adjustment of the four adjustable values of the belt cards. All values INCREASE by turning CLOCKWISE.
Ramp Adjustments
“Ramp Up” controls the time it takes the belt to accelerate to its set speed, and “Ramp Down” controls the time it takes the belt to decelerate to a stop. Adjustment is from 0 –5 seconds. Care must be taken if adjustment is made, since it is possible to have the feeder in a ramp cycle while the main is not running.
Factory setting:
1. Decrease all ramp screws (counterclockwise) to zero
2. Set ramp down on both cards to two full turns open (clockwise)
3. Set main ramp up to four full turns open (clockwise)
4.Set feeder ramp up to six full turns open (clockwise)
To be sure which way to turn the screws, remove a card and look at the adjustable resistor connected to the screws. Turn the screws counterclockwise so the sliding “slugs” in the resistors move to the end away from the black face plate of the card. There are no stops, so there is no way to turn too far. This is the zero point in step 1.
Max
The gain “MAX” screw adjusts the gain of the belt speed knobs. To check these adjustments, time the belts while running them at full speed with the manual by-pass. Next, run the belts with the remote to see if the same speed is reached. If the belt is slower, increasing the gain will speed the belt up.
STOP increasing the setting when the belt doesn’t go any faster. You can determine this by timing the belt, or just go by the sound of the belt. Turning the gain screw up too far narrows the adjustment “window” on the belt speed knobs. Therefore, if you have a belt that doesn’t run until “3” or “4,” and full speed is reached at “6” or “7,” set the knob at “10” and decrease the gain setting until the belt starts to slow down. This will open the “window” back up.
Zero
The zero screw calibrates the position of the feedback sensor. Whenever the e-stop circuit is reset, the LED’s on the belt motor controllers will be on. The ZERO setting positions the valves so that the belts are not running.
If the ZERO is too high, the belts can “creep” or run slowly when the belt switches are off. Pushing an e-stop will stop the belts. With the e-stop reset, adjust by turning the ZERO screw counterclockwise toward “-“, 1/8 turn at a time, until the belt stops.
If the ZERO is too low, a speed setting of “2” or “3” might be required to get the belt to move. Increase the ZERO setting until the belt just starts, then back off until it stops again. Subsequent adjustments might be necessary, due to change in resistance from the rollers, scrapers or skirts.
