The BPT-3B
Clutch/Brake Performance Tester
Operating Manual

Revised: May 14, 2003

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System Description Using the Brandes System Readout Cable
Functional Test Measuring Change in C/B Performance
Palm Switch Read Head Cable Assembly (Standard) Measuring Stopping Angle
Clutch-Trip Read Head Cable Assembly (Optional) Troubleshooting
"Minimum Safe Distance" Display Readout Parts List
"Clutch Engage Time" Display Readout Specifications
"Stopping Time" Display Readout Warranty

System Description Top

         OSHA press safety standards require that two-hand controls and presence-sensing devices be located at a minimum safe distance from the point of operation – the die closure zone.

         To establish the minimum safe distance, the time it takes the press to stop the slide after a STOP signal is initiated must be accurately measured. Also, unless the press is equipped with an automatic, built-in device for checking brake performance, OSHA requires that stopping time be checked weekly to make sure the brake is performing, as it should.

         The BPT-3B is a portable electronic instrument system used to accurately measure the stopping time and clutch engage time of part revolution, mechanical power presses and hydraulic presses.

Press stopping time can be measured to:

  1. Satisfy weekly OSHA maintenance inspection requirements;
    1910.217, subpart 0, (e) (1) (i) & (ii)

  2. Determine the stopping angle.

  3. Determine the change in brake performance.
Press clutch engage time can be measured to:

  1. Determine the change in clutch performance.
Press Minimum Safe Distance can be measured to:

  1. Satisfy weekly OSHA maintenance inspection requirements;
    1910.217, subpart 0, (e) (1) (i) & (ii)

  2. Set the "Minimum Safety Distance" of two-hand controls as required by OSHA
    regulations; 1910.217, subpart 0, (c) (3) (vii) (c)

  3. Set the "Minimum Safety Distance" of presence sensing devices as required by OSHA
    regulations; 1910.217, subpart 0, (c) (3) (iii) (e)
The system is stored in a carrying case with components consisting of:

  1. The BPT-3B, a lightweight, handheld, electronic measuring unit.
  2. The Palm-switch operated, Read Head Cable Assembly.
  3. 2 plastic measurement grids (length: 10 & 20 inches).
  4. Power adapter (12Vdc. – 500 mills).
  5. Magnetic base with gooseneck.
  6. Grid holder.
  7. Rugged carrying case.
  8. (Optional) Clutch-trip operated, Read Head Cable Assembly.

         The H&W Controls BPT-3B Clutch/Brake Performance Tester measures slide starting and stopping times directly. When a START signal is initiated, the electronic clutch timer starts, and the Read Head sensor becomes active. The clutch timer stops the moment the sensor detects movement of the measuring grid mounted on the press slide (ram). This is the actual clutch engage time to start slide (ram) movement. This time does not include clutch slippage after the point of slide (ram) movement. This time is displayed in the "Clutch Engage Time" display.

         When a STOP signal is initiated, the electronic brake timer starts and the Read Head sensor begins to scan the edges of the lines on the measuring grid. When the press slide (ram) comes to a complete stop, the sensor stops the timer. The "Stopping Time" display shows the actual braking time to stop slide (ram) movement. This time is displayed in the "Stopping Time" display. Push the "Display" button to view all three readings.

         A "Minimum Safe Distance" display is also included, which is controlled using the same method as the stopping time circuit described in the above paragraph. The stopping time is directly converted into the Minimum Safe Distance and displayed in the "Minimum Safe Distance" display.

         The BPT-3B is available with two different types of actuation methods. The standard "Palm-Switch Read Head Cable Assembly" is a unique design to allow quick setup without the need to wire into the press control circuits. This standard assembly figures the total clutch engage and braking times. The optional "Clutch-Trip Read Head Cable Assembly" is used when the press is required to be cycled in a mode other than INCH or SETUP. With this assembly, the press can be operated by ANY means of starting and stopping the slide (ram) (by pressing the Emergency Stop button, etc.). This method requires the connection of two wires to the press control clutch output (alligator clips are provided), and does not figure the control circuitry "engage" and "disengage" times.

        Because of the different types of actuation methods, the two read head cable assemblies are described in separate chapters in this manual. Before using the BPT-3B, spend a few minutes to become familiar with the electronic unit.
The buttons and displays have the following functions:

ON button ................................ Press to turn power on, press to turn off.
DISPLAY button ...................... Press to read all three display readings ("B" version).
TEST button ............................. Press momentarily to check internal calibration of the unit, fault
lights, circuitry, and displays.
RESET button .......................... Press to reset all displays to "000" and turn off both fault lights.
POWER light ........................... On with power on ("B" version).
Clutch Time FAULT light ......... When lit, indicates the clutch time has exceeded the maximum time
of the tester (1 second).
Stopping Time FAULT light ..... When lit, indicates the stopping time has exceeded the maximum time
of the tester (1 second).
CLUTCH TIME Display .......... Registers clutch engage time in thousandths of a second (.001).
STOPPING TIME Display ...... Registers stopping time in thousandths of a second (.001).
MINIMUM SAFE DISTANCE Display ... Registers minimum safe distance, as determined by OSHA,
in tenths of an inch (00.0).

Functional Test Top

         The backside of the electronic unit has instructions for functional test and operation (using the standard Palm Switch Read Head Cable Assembly).
         Remove the electronic unit from the carrying case. Allow the unit to reach room temperature, then, perform the following test prior to using:

  1. Plug power adapter into a 117Vac. receptacle (US model) and into the POWER input on the right side of the electronic unit.
  2. Press the ON button to turn on the unit. Press and hold the DISPLAY button ("B" version). All three displays should read "000" and both FAULT lights should be off. Allow the unit to sit for a minute for the circuitry to stabilize.
  3. Press the TEST button momentarily (if the Palm Switch Read Head Cable Assembly is plugged into the unit, do not actuate the palm switch or move the grid in the read head slot while the test is being performed). All three displays should instantly start counting, and the two FAULT lights flash rapidly. The "Clutch Engaged Time" and "Stopping Time" displays should lock out at "888" and the two FAULT lights, after that time, should remain on. The "Minimum Safe Distance" display should lock out at "63.0" (62.9 – 63.1 is OK). Recalibration is done at H&W Controls
  4. Push the RESET button momentarily. All three displays should reset to "000" and both FAULT lights should go out.

Using the Palm-Switch Read Head Cable Assembly Top

Setup

         The BPT-3B is setup on a press as described below. The electronic unit is positioned on the press in a spot to be easily viewed by the operator.

To setup the BPT-3B...

  1. Mount the magnetic base with gooseneck to the press bolster by its lock on/off lever.
  2. Attach grid holder to the end of the gooseneck by tightening the thumbscrew.
  3. Attach grid of the proper length to the grid holder. The grid is to be in a vertical position. Grid length must be greater than the press stroke. A 10" and a 20" grid are included in the kit. An optional 30" grid may be obtained from H&W Controls (The 30" grid will not fit in the briefcase.) Press strokes longer than the grid length can be measured (the sensor can leave the grid) as long as the grid is in the sensor during the clutch engage period, and during the full duration of the stopping time.
  4. Attach read head, by its magnetic base, to the press slide (ram) with the slot aligned vertically.
  5. Position the grid through the slot in the sensor. When properly setup, the grid does not move (touch the sensor) as the slide (ram) travels up and down. It may be necessary to cycle the press several times to align the grid in the sensor slot.
  6. Connect the cable from the read head sensor to the electronic unit.
  7. Plug the power adapter into the POWER input on the right side of the electronic unit, and into a 117Vac. receptacle (US model). An extension cord may be necessary.
  8. Press the ON button to turn on the electronic unit.

The BPT-3B is now ready to operate.

Operation

  • Set the press control to INCH (SETUP) mode.
  • Start the press motor and allow motor to reach its no-load RPM. Check the clutch and counterbalance air pressures for proper adjustment. On variable speed presses, set the speed to the maximum press speed used.
  • With slide (ram) at top-dead-center, hold the palm switch lightly against one INCH (RUN) button. Depress both INCH (RUN) buttons and the palm switch rapidly all at the same instant.
  • At 90 degrees of crankshaft rotation (halfway down), release pressure on the INCH (RUN) buttons and palm switch rapidly all at the same instant.
  • When the slide (ram) has come to a complete stop, press the DISPLAY button ("B" version) and record the three display readings.

             Repeat steps 3 to 5 ten times. It is not necessary to press the RESET button each time, as reset is automatic when step 3 is initiated. Take the average reading of each of the three sets of display readings.
    (Example: Add the ten "Clutch Engage Time" readings together, then divide by 10.)
             Disregard any significantly higher or lower readings and take new readings to replace them. Readings can vary depending on the position (angle) of the crankshaft when the start or stop signal is made. ALWAYS RELEASE THE PRESSURE ON THE INCH (RUN) BUTTONS AND PALM SWITCH AT 90 DEGREES DOWN FROM TOP POSITION TO OBTAIN THE CORRECT "STOP TIME" AND "MINIMUM SAFE DISTANCE" READINGS PER OSHA REQUIREMENTS.
             FAULTS: If either FAULT light flashes rapidly after a cycle, disregard all the display readings for that cycle and try again. This indicates an incorrect usage of the palm switch, misalignment of the grid in the read head slot, or too slow a press speed (must be above 15 spm.).

    CAUTION:

             If a two-hand inch control is used, always depress the INCH button with the palm switch on it LAST, and release the INCH button with the palm switch on it FIRST. If this is not done, the displays will show a higher clutch engage time or too slow a stop time and minimum safe distance.
             An invalid stopping time may also occur due to interference between dies. If a die closure should occur prior to full stop, remove the lower die prior to making measurements.

    Using the Clutch-Trip Read Head Cable Assembly Top

    Setup

            The BPT-3B is setup on a press as described below. The electronic unit is positioned on the press in a spot to be easily viewed by the operator.

    To setup the BPT-3B...

    1. Mount the magnetic base with gooseneck to the press bolster by its lock on/off lever.
    2. Attach the grid holder to the end of the gooseneck by tightening the thumbscrew.
    3. Attach grid of the proper length to the grid holder. The grid is to be in a vertical position. Grid length must be greater than the press stroke. A 10" and a 20" grid are included in the kit. An optional 30" grid may be obtained from H&W Controls (The 30" grid will not fit in the briefcase.) Press strokes longer than the grid length can be measured (the sensor can leave the grid) as long as the grid is in the sensor during the clutch engage period, and during the full duration of the stopping time.
    4. Attach read head, by its magnetic base, to the press slide (ram) with the slot aligned vertically.
    5. Position the grid through the slot in the sensor. When properly setup, the grid does not move (touch the sensor) as the slide (ram) travels up and down. It may be necessary to cycle the press several times to align the grid in the sensor slot.
    6. Connect the cable from the read head sensor to the electronic unit.
    7. Connect the two alligator clips on the Clutch Trip Read Head Cable Assembly to the 110-120Vac. clutch valve output terminals in the existing press control box (an electrician may be required to determine the locations). The clips should be connected directly across the clutch valve (on a dual channel system, use either one of the valve outputs).
    8. Plug the power adapter into the POWER input on the right side of the electronic unit, and into a 117Vac. receptacle (US model). An extension cord may be necessary.
    9. Press the ON button to turn on the electronic unit.

    The BPT-3B is now ready to operate.

            Most press controls have an auto-topstop feature built into them in the INCH/SETUP mode to meet current OSHA requirements *. Because of this, some presses do not reach full speed during the ¼ inch stroke to the 90-degree position for checking stopping time and minimum safe distance. This is one of the reasons H&W Controls designed the "Clutch Trip Read Head Cable Assembly" **.
            With this BPT-3B operating method, the press can be cycled in ANY press mode, and the slide (ram) started and stopped using ANY means. Hence, the press may be cycled in the CONTINUOUS mode and the slide (ram) stopped by pressing the EMERGENCY STOP button at the 90-degree position.
            Another reason for using this operating method is it's consistent accuracy. Although it does not check the press control circuitry engage and disengage times, the clutch/brake engage and disengage times are measured more accurately because the operating means is controlled automatically from the clutch output.
             For safety, the "Clutch Trip Read Head Cable Assembly" is electronically isolated from the BPT-3B electronic unit using an Opto-isolator.
            Adequate space is provided in the storage case (briefcase) for both the "Clutch Trip Read Head Cable Assembly" and the "Palm Switch Read Head Cable Assembly" for convenience.

    *   Reference 1910.217 (b) (7) (iv) (v) (c)
    ** Option #501918A1


    Operation

    1. Start the press motor and allow motor to reach its no-load RPM. Check the clutch and counterbalance air pressures for proper adjustment. On variable speed presses, set the speed to the maximum press speed used.
    2. Cycle the press in the mode preferred, and using whatever starting and stopping method. Make sure to allow enough time in between engagements and disengagements for the slide (ram) to reach full speed. The slide (ram) should always be stopped at the 90-degree position (half way down) to determine the correct stopping time and minimum safe distance per OSHA requirements.
    3. When the slide (ram) has come to a complete stop, press the DISPLAY button ("B" version) and record the three display readings.

             Repeat steps 1 to 3 ten times. It is not necessary to press the RESET button each time, as reset is automatic when step 2 is initiated. Take the average reading of each of the three sets of display readings. (Example: Add the ten "Clutch Engage Time" readings together, then divide by 10.)
             Disregard any significantly higher or lower readings and take new readings to replace them. Readings can vary depending on the position (angle) of the crankshaft when the start or stop signal is made. ALWAYS STOP THE PRESS SLIDE (RAM) AT 90 DEGREES DOWN FROM TOP POSITION TO OBTAIN THE CORRECT "STOP TIME" AND "MINIMUM SAFE DISTANCE" READINGS PER OSHA REQUIREMENTS.
            FAULTS: If either FAULT light flashes rapidly after a cycle, disregard all the display readings for that cycle and try again. This indicates an incorrect usage of the palm switch, misalignment of the grid in the read head slot, or too slow a press speed (must be above 15 spm.).

    "MINIMUM SAFE DISTANCE" Display Readout Top

            OSHA regulation 1910.217 (c) (2) (vii) (3) (e) requires the placement of two-hand control and presence sensing devices at a distance from the die pinch point such that an operator cannot reach the pinch point until after the slide (ram) has come to a complete stop. For convenience, H&W Controls has included a display readout, which indicates this "MINIMUM SAFE DISTANCE" for instant location of these devices. Reference 1910.217 (c) (3) (iii) (e)
            The circuitry, which operates the "MINIMUM SAFE DISTANCE" display readout, is calibrated to OSHA specifications and should not be tampered with. Any calibrating should be done at H&W Controls.
            The minimum safe distance is measured in a straight line from the two-hand control or presence sensing device to the pinch point of the die closest to the operator.
            WHEN OPERATING THE BPT-3B, THE PRESS SLIDE (RAM) MUST BE STOPPED AT THE 90 DEGREE (HALF WAY DOWN) POSITION, TO DETERMINE THE CORRECT MINIMUM SAFE DISTANCE PER OSHA REQUIREMENTS.
            The minimum safe distance should be checked weekly on each and every operating press per OSHA requirements. Reference 1910.217 (e) (1) (i) & (ii).

            Per OSHA requirements, new installations of two-hand control or presence sensing devices should have a tolerance added to the actual minimum safe distance (which is indicated by the BPT-3B) to allow for tolerable brake wear. This tolerance is 10% for NEW brake installations, and 5% for existing or partially worn brake linings. This will provide a margin to insure a safe operation. Reference 1910.217 (c) (3) (iii) (e) & (viii) (c).
            Be sure to add the correct tolerance to the "Minimum Safe Distance" reading on the BPT-3B before measuring the distance for two-hand or presence sensing device (light curtain) placement.

    "CLUTCH ENGAGE TIME" Display Readout Top

             The BPT-3B contains a separate display to monitor the "Clutch Engage Time" at each clutch engagement. This time is the actual clutch engage time, from the point of the actuation signal, to the first sign of movement of the slide (ram). This time does not include clutch slippage after the point of movement.
            This display readout can be helpful in determining clutch lining wear and lining life remaining by recording this reading during the weekly minimum safe distance checks. These recordings, collected for each press, over a long period of time, will indicate trends in clutch wear and give an indication of the remaining number of press cycles before a clutch (lining) is to be replaced.
            A FAULT light is included with the "CLUTCH ENGAGE TIME" display, which will light if the display (clutch time) exceeds its maximum reading (999 milliseconds). The display will also lock out at "000". The FAULT light will flash rapidly if an error is detected during the clutch time check.

            IF EITHER THE "CLUTCH ENGAGE TIME" OR "STOPPING TIME" FAULT LIGHTS FLASH RAPIDLY, DISREGARD ALL THREE DISPLAY READINGS!

    "STOPPING TIME" Display Readout Top

            The separate "STOPPING TIME" display readout monitors the total stopping time of the slide (ram). This display is triggered by the clutch disengagement signal (the release of the palm switch). The display stops counting when the slide (ram) motion completely stops. This display is required for monitoring brake performance per OSHA requirements in regulation 1910.217. The stopping time is to be checked weekly.
            A FAULT light is included with the "STOPPING TIME" display, which will light if the display (stopping time) exceeds its maximum reading (999 milliseconds). The display will also lock out at "000". The FAULT light will flash rapidly if an error is detected during the stopping time check.

            IF EITHER THE "CLUTCH ENGAGE TIME" OR "STOPPING TIME" FAULT LIGHTS FLASH RAPIDLY, DISREGARD ALL THREE DISPLAY READINGS!

    Using the H&W System Readout Cable Top

    (Optional)

            The H&W press control systems, such as the System 4000 or EBM-100A B/M Monitor, can be equipped with a readout receptacle on the front of the cabinet. The optional "System Readout Cable" can be plugged into this receptacle and directly into the BPT-3B electronic unit. The BPT-3B will automatically read out the "Clutch Time", "Stopping Time", and "Minimum Safe Distance" at every clutch engagement and disengagement. No read head assembly or grid is required.
            The "System Readout Cable" can be used with the same accuracy as the grid setup and read head assembly when" Measuring Change in Clutch/Brake Performance" as described below.

    Measuring Change in Clutch/Brake Performance Top

            With a clutch or brake in good condition, the BPT-3B typical display reading may be "300". When the clutch or brake has deteriorated, the average reading may be "400". These readings show the "Relative Increase in Press Clutch or Brake Time".

    Example formula: 400/300 = 1.33 or 33%

            Data thus collected and plotted for each press over a long period of time will indicate trends in clutch and brake wear and give an indication of the remaining number of press cycles before a clutch or brake is to be replaced.
            NOTE: Any variations in operating air/hydraulic pressure, counterbalance, and slide (ram) position will effect estimates in determining lining wear. Be sure to note and maintain the same pressures and positions at each measurement.

    Measuring Stopping Angle Top

            The "STOPPING TIME" display readout can be used to determine the angle the crankshaft travels in stopping, i.e., stopping angle. The stopping angle can be calculated from the following equation (RPM is the crankshaft speed, and K is a factor supplied by the brake manufacturer reflecting variations in friction of the linings, accounting for the non-linearity of the braking action. 1.5 appears as a good average.).

            STOPPING ANGLE in degrees = 3/K x RPM x STOPPING TIME in seconds

            EXAMPLE:
            (If K = 1.5, RPM = 60, STOPPING TIME display = "300")
            2 x 60 x .300 = 36 degrees

    Troubleshooting Top

    Testing the BPT-3B

    1. With the power adapter plugged in, and the POWER switch pressed on, push the DISPLAY button ("B" version). All three display readouts should read "000", with the decimal point lit between the last two digits on the "Minimum Safe Distance" display ("00.0").
    2. With the power on, check the internal time calibration by pressing the TEST button and DISPLAY button ("B" version). The "Clutch Engaged Time" and "Stopping Time" display readouts should both read "888". The "Minimum Safe Distance" display readout should read "63.0" (62.9 – 63.1 is OK). If not, recalibration or repair is needed (send to Brandes Controls). Press the RESET button. All three displays should reset to "000".
    3. With the "Palm Switch Read Head Cable Assembly" plugged into the electronic unit, press and hold the palm switch. Push the DISPLAY button ("B" version). The "CLUTCH ENGAGE TIME" display readout should count up to "000" and lock out, and the "Clutch Engaged Time" FAULT light should light. (During this procedure, do not have/move the grid in the read head slot.)
    4. While moving the grid through the read head slot, release the palm switch (the grid must be constantly moving). Push the DISPLAY button ("B" version). The "STOPPING TIME" display readout should count up to "000" and lock out, and the "Stopping Time" FAULT light should light. The "Minimum Safe Distance" display readout should read "63.0" (62.9 – 63.1 is OK).
    5. Press the palm switch again, but this time release the palm switch before the "CLUTCH ENGAGE TIME" display readout reaches "000" (During this procedure, do not have/move the grid in the read head slot). Both FAULT lights should flash rapidly. The "CLUTCH ENGAGE TIME" display readout should lock out at the present count, and the "STOPPING TIME" and "MINIMUM SAFE DISTANCE" displays should read "000".
    6. Press the RESET button. All three display readouts should read "000", and both FAULT lights should go out.

    The BPT-3B is functioning properly if steps 1 through 6 check out as described.

            Inside the BPT-3B is a .5 amp fuse (F1) for safety. The fuse is replaceable by first removing the six Philips head screws from the back cover. The fuse should be replaced with the same type for continued safety. Replace with Littlefuse .5 amp, slow-blow type.

    Parts List Top

    Standard Accessories

    BPT-3B kit, complete BPT-3B
    Carrying case (with label) 500728A1
    Grid (10") 500818A1
    Grid (20") 500818A2
    Grid Holder 500916A1
    Magnetic Base with Gooseneck 500712A1
    Palm Switch Read Head Cable Assembly 501917A2
    Electronic Unit, BPT-3B 556500A1A
    Main Control Board Assembly 556000A1A
    Driver Board Assembly 556100A1A
    Power Adapter (12Vdc. – 500 mills) 500707A2
    Manual, Instruction OM-150

    Optional Accessories

    Grid (30") (Does not fit in carrying case) 500818A3
    Clutch Trip Read Head Cable Assembly 501918A1
    Control Readout Cable 500971A2
    Control Readout receptacle, installed in H&W controls (System 4000, EBM-100A B/M Monitor) 500961A1A


    BPT-3B Specifications Top

    Clutch Engage Time range 000 – 999 milliseconds
    Stopping Time range 000 – 999 milliseconds
    Minimum Safe Distance range 00.0 – 63.0 inches
    Measured stroke range .5 – 19 inches (optional to 29 inches)
    Minimum measuring speed 0.84 inches per second
    Operating temperature 60 – 100 degrees F ("B" version = 40 – 100 degrees F)
    Storage temperature 40 – 120 degrees F
    Displays 3 digit LED x 3
    Power requirement 110 – 120Vac. @ .05 amps
    Clutch Engage Time calibration reading 888 milliseconds
    Stopping Time calibration reading 888 milliseconds
    Minimum Safe Distance calibration reading 62.9 – 63.1 inches
    Clutch Engage Time accuracy (palm switch) .008 seconds *
    Stopping Time accuracy (palm switch) .008 seconds *
    Minimum Safe Distance accuracy (palm switch) .5 inches *
    Clutch Engage Time accuracy (clutch trip) .001 seconds
    Stopping Time accuracy (clutch trip) .003 seconds
    Minimum Safe Distance accuracy (clutch trip) .18 inches
    BPT-3B overall accuracy .007 seconds
    Weight 13 lbs. (15.5 lbs. shipping weight)
    * Affected by human reaction time. Readings may vary slightly.

    Warranty Top

             Seller makes NO WARRANTY OF MERCHANTABILITY OR OF FITNESS FOR ANY PURPOSE, AND NO OTHER EXPRESS OR IMPLIED WARRANTIES, which extend beyond the description contained in seller's quotation. Any equipment or components manufactured by Seller and proving defective in material and/or workmanship within one year from the date of shipment will be, at Seller's option, repaired, replaced, or the purchase price refunded; provided written claim in respect of such equipment is made promptly by Buyer within said period, use of such equipment is promptly discontinued, and provided equipment has been installed, operated and maintained in accordance with generally approved practice and in accordance with Seller's instructions. Adjustments for items of equipment not manufactured by Seller shall be as provided by the standard warranty of the manufacturer or supplier thereof.
            Notwithstanding any breach of contract or negligence on the part of the Seller, the forgoing constitutes the sole obligation of Seller and the sole remedy of Buyer. Any cause of action arising hereunder must be commenced within one year from the date of the breach.

     

    H&W CONTROLS
    A Division of Henry & Wright Corporation
    739 East 140th Street - Cleveland, OH 44110
    Phone: 216-851-3750 Fax: 216-851-3970

    H&W Controls 2000
    All Rights Reserved