Telebelt Belt Tracking Troubles? Wearing out your rollers?

A few questions recently came in from a customer concerning belt tracking and wearing out of rollers on their TBS 130. These issues and resolutions apply to all ”active feeder” model Telebelts - TB 80, TB 110, TB 130, TB 600, TBS 130 and TBS 600. Let’s go over their issues, and how to fix them.

Issue 1: On the feeder belt, there are 2 gangs of 3 roller sets,  and for some reason, we are having to change out 2 of the three sets every 2 weeks (the belt is wearing on the shafts that the rollers are on). We checked our other two belts and they are not having this issue.

Resolution: The feeder triple rollers are directional.  Each side roller is set at a slightly different angle. Make sure the end with the widest (lowest) offset faces the hinge.  In other words, the wide offsets face each other (see left).  If mounted in reverse, only the narrow set contacts the belt, and I can see the possibility of the belt being pulled down to the shaft, especially with this thinner type of belt. The photo looks like the belt flattens out, going left to right. If that is the case, the triple roller is in  backwards.

 

Issue 2: On the main belt, when you have the boom extended, the belt tracks with no problems (stays centered on the roller). When you retract the boom, upon getting to the last two sections, the belt tracks to one side of the roller and rides there until you extend it back  out. We checked the belt tension and its sitting at 1,200 psi.

Resolution: Don’t over-tension the belt. The manual calls for 1,500 – 1,800 psi on the feeder. I instruct operators to go to the low end; 1,500 psi. Training (belt alignment) of the pulleys, with the boom extended, is very difficult. In this position, the head pulley of one section is very close to the tail pulley of the next. A centered belt can mean the pulleys are working against each other, or adjustment is correct – There is no way of telling.

DO NOT ATTEMPT ADJUSTING A BELT, OR CLEANING OF ROLLERS AND PULLEYS, WHILE THE BELT IS MOVING. Shut the belt off and push the E-Stop to make the adjustments or do the cleaning.

Never train pulleys unless the belt tension is first confirmed. A loose belt wanders on the pulleys, and attempts to train it will not succeed. Again, I suggest 1,000 psi, which is the low end of the 1,000 – 1,200 specification for the main belt (the slightly reduced tension yields longer splice life). Train the pulleys with the boom retracted as far as possible. Telebelts use crowned (tapered) pulleys. They are self-training, since each half of the belt is trying to run off the end of the pulley. This allows us to go without side idlers, which we have no room for . When the belt gets loose, the side that contacts harder pills the belt to that side.  Again, tension the belt first. This will take care of training problems.

A properly tensions and trained belt will not go out of alignment. Training is usually only required if a pulley is replaced. Grout buildup on the pulleys can also cause alignment problems, so keep them clean.

Issue 3: After adjusting the tension in all of our belt, the belt tracks fine when you extend the boom past the first section (it stays centered on the rollers without any problems), but if we have the belt rolling without extending anything, the belt seems to run on the one side of the pulley. Also, when you bring the boom back in and reach the second section, it moves over.

Resolution: When extending and retracting with the belt stopped, the belt can wander on the pulleys, When running, it should stay centered. Extend arm 2 partially and check the adjustment of the heel of arm 2 and the head of arm 1. If they are ok, extend arm 2  enough to gain access to the heel pulleys of 3, 4, and 5 since they are still bundled together. Check them and then check the remaining head pulleys.

DO NOT attempt to train the 12″ main drive pulley with the large adjustment bolts. This is a straight pulley, not crowned. Adjustment is made on the 5″  roller at the heel of arm 1. If the belt is centered on it it will be centered on the drive pulley.

 

Setting Telebelt Feeder Lift Pressure Switches

Function:  When the main conveyors are slewed, the brakes on both the feeder and the main release.  If this happens with the feeder off the ground, the feeder will:
a) swing behind the main conveyor like a real long counterweight, or
b) take off downhill if the machine is not level.

The feeders are raised hydraulically, but they lower by gravity as the oil passes through an orifice.  The feeders must be fully lowered for the mains to slew.  It looks like you are “powering down,” but you’re just letting the cylinder and rails relax.

If there is enough pressure in the feeder elevate circuit, the (NC) pressure switches open and break the connection to the slewing valve.  The WBV valve still goes to the “boom” side.  One switch disables slew right and the other disables left, and they are both connected to the feeder lift line through a manifold block.  No oil flows to release the brakes when the slewing valve doesn’t throw.

Symptoms:  Main will not slew left, but slew right works, or vice-versa.  It’s very rare for the main to not slew in either direction because of pressure switch adjustment, but it can happen if there is enough pressure on the system.  All functions work manually.  Cable remote makes no difference.

 “Field Fix” (to complete a pour):

  1. Make sure the feeder is down fully.  All pressure must be off the feeder elevate cylinder.
  2. After confirming feeder is firmly on the ground, try manual control.  Make sure to move the WBV (selector valve) andthe slewing valve.  If it still doesn’t slew, the problem is not the pressure switch.  If the main does slew, options are:
    1. Operate slewing manually to finish the pour.  Keep the feeder firmly on the ground while slewing the main.
    2. Bypass the pressure switches by:
      1. Removing the plug connector from the top of one the switches.  On a 110, it might be necessary to remove the fan shroud to do this.  If the problem is unchanged, that is the correct plug.  If it now won’t swing either way, replace that plug and remove the other one.
      2. Put a jumper wire between pin 1 and pin 2 of the plug.  A piece of tie wire will do.  Do not reconnect the plug, but tie it out of the way to keep it from shorting.
    3. Alternate bypass – Jump X10-17 to X10-18 for right or X10-19 to X10-20 for left.
    4. This is a temporary fix and permanent repairs MUST be made before taking the unit out again. 

     

    Procedure for Setting Telebelt Feeder Lift Pressure Switches

    NOTE: THIS PROCEDURE CAN ONLY BE PERFORMED WHEN THE SWITCH IS INSTALLED IN THE CIRCUIT. THESE ILLUSTRATIONS ARE MERELY FOR SHOWING THE SWITCH.

    The feeder lift pressure switches are installed to prevent the main boom from slewing when the feeder is off the ground.  This is a safety system.  The switches are installed in the feeder elevate hydraulic circuit.

    To set the switches, you need a continuity tester, 1/8” Allen wrench and a flat-head screwdriver.

    Procedure:

      1. Support machine with outriggers.
      2. Unstow the feeder from the rest on top of the main boom and slew feeder to side of machine.
      3. Lower empty feeder (NO HOPPER OR ATTACHEMENTS) until the feeder legs are 1 to 2 feet off the ground.
      4. Turn off the remote.  The truck engine can also be shut off.
      5. Remove wire connection plugs from both switches.
      6. Remove small brass screw adapters from both switches.  These are the adapters that the plugs screw in to. 

      1. Connect a continuity tester to terminal #1 and #2 (terminals are labeled on switch and plug)

      1. With 1/8” Allen wrench, turn the pressure adjustment screw in, (screws are located under the brass screw plug you removed), until you get continuity, then back screw out until you loose continuity.  From this point, back the adjustment screw out ½ turn more, this is your final setting.

    1. Repeat steps 8 on the other switch.
    2. Reinstall the brass screw adapters and wire connection plugs.
    3. Restart the engine, reset the remote and test the settings by lowering the feeder to the ground, then lift main boom out of the boom rest and slew main boom to the right and the left.  The main boom should slew.  Then raise the feeder off the ground and slew main boom right and left.  The main boom should not move.

Telebelt Belt Card Adjustments

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):

A370160KUNIFIEDCRTLBOX 06

A370160KUNIFIEDCRTLBOX14

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.

TelebeltBeltCard

Telebeltbox

TelebeltBoxCloseUp

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.

TelebeltRemoteControl