Otis DSD 412 DC Elevator Drive

Fault 117 occurs if serial communication does not start within 20 seconds after drive reset or power up. Fault 118 occurs if a valid serial communication message is not received for more than 150 milliseconds.

The drive has delivered excessive motor amps for a significant period of time. This fault does not automatically shut down the drive, but is annunciated via the ALARM relay output K2.

The measured motor field current exceeded 125% of the rated current, as defined by parameter #50. This can indicate issues with the motor field, current regulation, or power circuit.

The Loop Contactor auxiliary contact failed to pick up or drop out within the designated time, as requested by the DSD 412 drive. The detection time is set by Function #102, which can be 450ms or 3 seconds.

The Drive and Field Enable control circuit at TB1-9 was active for 5 minutes without the drive starting. This condition can cause motor field burnout.

A large current error existed for ½ second, indicating an open circuit within the motor armature path. This prevents proper motor operation.

The Safety Circuit, wired between TB3-1 and TB3-6 on Power Supply A4, was not closed for 100 milliseconds before a “Drive Run” command, or it opened unexpectedly while the loop contactor was closed.

The input AC line voltage sagged more than 10% below the nominal line voltage as set at parameter #9. This does not shut down the drive but is an indication that work is needed to avoid future F904 Low Line faults.

The Counter Electromotive Force (CEMF) of the motor exceeded 109% of the measured AC input voltage to the drive. This is a warning only and does not cause an automatic drive shutdown.

The Counter Electromotive Force (CEMF) of the motor exceeded 118% of the rated AC voltage to the drive. This fault indicates a miss-operation causing speed overshoot. This fault causes a drive shutdown to prevent fuse blowing.

The PCU processor was unexpectedly reset. This can be due to improper PCU connections, incorrect software, hardware issues with the main circuit card, or external noise interference. If the problem persists, the Drive Control PCB may need replacement.

A large speed error existed for a significant period of time. Speed errors larger than Function #100, for longer than Function #99 seconds, will cause a Speed Error Trip and automatic drive shutdown.

More than 5 automatic resets were necessary in less than 20 minutes of accumulated time. An accumulation of 5 counted faults will cause this fault and require a manual reset for continued operation.

The actual field current is failing to track the field current command by more than F192 (default = 0.05PU) for 5 seconds. This is not a shutdown fault, but a warning.

The PCU (U13, U14) version and/or revision is incompatible with the DCU (U39, U40) installed in the drive. This typically indicates a mismatch in EPROM versions.

The contactor failed to close or opened unexpectedly, or the motor voltage exceeded 30% of the rated motor voltage (parameter #7) during Self-Tune #997. This sets the Severe Fault flag, forces the DSD 412 current reference to zero, and shuts down the drive.

Current flow in excess of 300% of the rated armature current is detected within the armature circuit. This indicates a severe overload, a fault in the motor, or a measurement error.

The Low Voltage Power Supply (A4) output has dropped below 60% of its rated voltage, leading to a drive shutdown. A CPU Reset is required after the cause of the fault has been rectified.

The Phase Locked Loop (PLL) has lost synchronization with the 3-phase AC input power supply. This sets the Severe Fault flag, forces the DSD 412 current reference to zero, and shuts down the drive. This fault is generally caused by AC input power problems, is often self-correcting, and may occur in conjunction with an F904 fault. A CPU Reset is required.

The AC input power has dropped below 80% of the Nominal AC Line Voltage (parameter #9) for three consecutive cycles, or below 50% for a single cycle. This sets the Severe Fault flag, forces the DSD 412 current reference to zero, and shuts down the drive. This fault will often occur concurrently with an F903 fault.

The field current feedback has dropped below 80% of the expected current under specific operating conditions: during Field Weakening Mode (top speed, parameter #49), Full Field Mode (acceleration or deceleration, parameter #50), or Standing Field Mode (not running, parameter #53). This fault will shut down the drive.

The update mechanism for the Dual Port RAM from the Drive Control Unit (DCU) is unreliable. This condition necessitates the replacement of the Drive Control PCB (A1) and will shut down the DSD 412 drive. A power down is required.

The thermistor used for temperature sensing is detected as either open or shorted. This fault can also occur if the ambient machine room temperature is below 0°C, causing the detected resistance to be abnormally high. On larger drives, an open thermostat will also trigger this fault. This fault will not shut down the drive.

The calculated SCR junction temperature, derived from thermistor heat sink measurements and the heating effects of the measured armature output current, has exceeded 125 degrees Centigrade. This fault will not shut down the drive.

Repeated instances of high peak-to-average motor armature current are detected. This condition can be caused by defective hardware, inadequate regulator tuning, or other oscillatory operating conditions.

One or more of the three AC line fuses are open. This condition is checked during power-up and can be requested via the PCU F#998 Diagnostics function. Detection is achieved by measurements from voltage dividers on the Armature Interface PCB (A2).

One of the SCR/Doubler packs has a short circuit between the SCRs. This condition is checked only upon request through the PCU #998 Diagnostics CDU function. The optional handheld PCDU can also identify the specific SCR pair that is faulty. A DSD Power Down is required.

One of the SCRs in the system is not conducting current as expected. This condition is checked only upon request through the PCU #998 Diagnostics CDU function. The optional handheld PCDU will also identify which specific SCR pair is faulty. A DSD Power Down is required.

One of the critical parameters, specifically Rated Volts (#7 or #9) or Rated Current (#3 or #50), has been set outside the acceptable operating range for the chassis hardware. A DSD power down is required.

This fault occurs when the 'prohibit rotation' bit was removed while the control loop was already picked-up (active). This condition can only be triggered when operating the drive via the handheld PCDU.

This fault is indicated during the F998 PCU Diagnostics Test. It signifies that the polarity of the Armature Voltage Feedback wires is reversed or that the wires are missing. Failure to correct this can lead to F909 faults and/or poor drive performance. A DSD power down is required.

This fault is declared if the numerical value entered for the Rated Line Voltage (parameter #9) falls outside the acceptable range of 150 to 525VAC. Entering a value of 0 will default the rated voltage to either 230 or 460 VAC based on the sensed line voltage. A DSD power down is required.

This fault is declared if the value entered for the Rated Armature Voltage (parameter #7) is outside the acceptable range of 150 to 700 VDC. A DSD power down is required.

The system is unable to identify the drive's size. The bridge type, ampere rating, and current feedback scaling are determined by a sense resistor on the Cube ID PCB, which plugs into the A2 Armature Interface PCB. This fault occurs if the computer cannot identify this physical hardware. A DSD power down is required.

This fault is declared if the number entered for Rated Armature Current (parameter #3) is outside the acceptable range of 0.125 to 2.0 times the bridge current rating, which is determined by the bridge sense resistor on the Cube ID PCB located on the Armature Interface PCB. A DSD power down is required.

This fault is declared if the number entered for Rated Field Current (parameter #50) is outside the acceptable range for the Field Interface board (A3) current rating. This rating is determined by the field sense resistor selected by SW1 on the Field Interface PCB. A DSD power down is required.

The field bridge rating is determined by a sense resistor on the Field Interface board, selected by SW1, which sets the motor field current feedback scaling for the A/D converter. If this resistance value is not recognized, a Field Sense Fault is declared, indicating a hardware fault on the Field Interface PCB, Drive Control PCB, or interconnecting cables and hardware. A DSD power down is required.

The motor speed has exceeded the trip level configured in parameter #1, #11, or #12. Parameter #12 is a percentage of the motor speed value set in parameter #1, as measured by the encoder.

The DSD 412 drive does not detect encoder velocity in proportion to the armature voltage, indicating a loss of speed feedback. This fault is related to functions #14 and #15.

The digital encoder signals and motor voltage signals do not agree in their indicated direction of rotation. This typically points to a reversal in the encoder's directional feedback wiring.

This fault indicates that the main loop contactor has failed to pick (close) after the drive has been commanded to run. This prevents the armature circuit from being energized, thereby inhibiting motor operation. The drive detects this if the field current (referenced by setting #32) is not sufficient to pick the contactor.

This fault is triggered when the Safety-Chain circuit, which is critical for safe operation, becomes open at any point during an elevator run or is not closed at startup. An open Safety-Chain immediately disables the drive, causes the loop contactor to drop, and halts all motor activity.

This fault is triggered if the motor armature circuit is not closed before the "Loop Confirm" signal asserts, preventing the drive from establishing a closed current path to the motor. It indicates a disconnection that inhibits motor operation and often occurs during the drive's startup sequence.

The PCU detected one or more open AC fuses. This fault indicates a critical interruption in the AC power supply to the drive.

The PCU detected one or more shorted SCR/doubler packs. This indicates a failure within the power conversion stages of the drive.

The PCU detected one or more open SCR/doubler packs. This indicates a failure within the power conversion stages of the drive, preventing proper current flow.

The PCU detected reversed Armature Feedback wires. This fault also occurs if the Armature Feedback wires are not connected, leading to incorrect armature voltage sensing.

This fault indicates that the motor's armature circuit is detected as open when the "Loop Confirm" signal activates, typically during the initial pre-loading sequence. This condition prevents the drive from establishing proper control of the motor and indicates a critical disconnection in the power path.