Technical Specifications

FAQ

1. What is the primary function of the 1336-SN-SP8A?
The 1336-SN-SP8A is a converter snubber circuit board designed for compatible Allen Bradley 1336 STEF drive systems. It is installed in the converter-side power circuit and is used to suppress voltage transients and switching spikes generated during power-device operation. When semiconductor devices switch rapidly, parasitic inductance and capacitance within the power circuit can produce short-duration voltage spikes. The snubber circuit helps control these transient conditions, reducing electrical stress on associated power components and supporting more stable operation of the drive.

2. Which Allen Bradley drive configurations are compatible with the 1336-SN-SP8A?
The 1336-SN-SP8A is associated with 1336 STEF Frame E configurations and is used with compatible 1336 Plus, 1336 Plus II, 1336 Impact, and 1336 Force drive systems. Compatibility should always be verified using the complete drive catalog number, frame designation, voltage rating, power rating, and original circuit board part number. Different 1336 configurations can use different snubber assemblies, so a board that looks similar should not automatically be considered a suitable replacement.

3. What voltage and power range is associated with the 1336-SN-SP8A?
The 1336-SN-SP8A is used with applicable 230 VAC, 460 VAC, and 575 VAC 1336 STEF drive configurations, with an associated power range of approximately 150–250 HP. The actual drive rating must be confirmed from the complete drive model because voltage and horsepower alone do not establish compatibility. Frame configuration, power circuit design, and the original snubber assembly should also be checked before selecting a replacement.

4. Is the 1336-SN-SP8A a converter snubber or an inverter snubber?
The 1336-SN-SP8A is a converter snubber circuit board. It is intended for the converter-side power circuit rather than the inverter output section. The converter section handles the input-side power conversion before the DC bus, while the inverter section converts DC bus power into controlled AC output for the motor. Although both converter and inverter snubbers are designed to reduce voltage transients, their electrical positions and applications are different. Therefore, an inverter snubber should not be substituted for the 1336-SN-SP8A without confirming the complete electrical compatibility.

5. What symptoms may indicate a problem with the 1336-SN-SP8A?
A defective 1336-SN-SP8A may contribute to converter-related faults, abnormal voltage transients, unexpected drive trips, or unstable operation under changing load conditions. Physical inspection may show burned components, PCB discoloration, overheating, electrical arcing, or damaged connections. However, these symptoms do not necessarily mean that the snubber board is the original cause of the problem. Rectifier devices, DC bus components, incoming power abnormalities, wiring faults, and other power-circuit problems can produce similar symptoms. Proper troubleshooting should therefore evaluate the complete converter circuit before replacing the board.

6. What should be checked before replacing the 1336-SN-SP8A?
Before replacement, verify the 1336-SN-SP8A part number and confirm that the drive is configured for the appropriate 1336 STEF Frame E application. Inspect the original board for burned components, cracked parts, discoloration, overheating, electrical arcing, and damaged connectors. The associated converter power components, wiring, input supply, and DC bus should also be checked if the original board has suffered significant damage. Identifying the underlying failure is important because replacing the snubber board without correcting another power-circuit problem may result in repeated failure of the replacement component.

7. What safety precautions are required when servicing the 1336-SN-SP8A?
The 1336-SN-SP8A is installed inside a high-energy variable frequency drive, so the equipment must be properly shut down, isolated, and discharged before the circuit board is accessed. Disconnecting the incoming power does not immediately eliminate all hazardous voltage because the drive’s DC bus capacitors can retain stored electrical energy. The specified discharge period should be observed, and residual voltage must be verified with appropriate test equipment before touching internal components. Proper lockout/tagout procedures and ESD protection should also be used. Internal drive maintenance should only be performed by personnel with appropriate electrical training and experience.

8. What checks should be performed after installing a replacement 1336-SN-SP8A?
After installation, confirm that the snubber circuit board is correctly positioned and securely mounted. Check all connectors, terminals, and associated wiring for correct placement and secure connections. Before energizing the drive, inspect the internal power section for loose hardware, foreign objects, damaged wiring, or evidence of overheating. After safe power-up, check the drive status and fault indications before beginning normal operation. Perform a controlled startup and gradually introduce the operating load while monitoring voltage, current, temperature, and protective functions. If converter-related faults remain after replacement, further inspection should include the input power circuit, rectifier components, DC bus, wiring, and other related protection circuits rather than repeatedly replacing the snubber board.