Allen Bradley Control Circuit Transformer 1497 User Manual

Content

Allen Bradley Control Circuit Transformer 1497 Manual

The Allen-Bradley Bulletin 1497 control circuit transformer is a single-phase industrial transformer designed to provide reliable, isolated control power for motor starters, contactors, relays, solenoid valves, programmable controllers, and other control devices. It reduces a higher supply voltage to a suitable control voltage while helping maintain dependable operation during equipment starting and switching events.

The Bulletin 1497 family includes multiple primary-voltage, secondary-voltage, VA-rating, fuse-block, and enclosure configurations. Depending on the catalog number, available features may include single, dual, or multitap primary connections, epoxy-encapsulated construction, finger-safe terminals, and optional primary or secondary fuse blocks. The product family covers applications from compact control panels to larger industrial machine systems.

This manual is intended for electricians, panel builders, controls engineers, maintenance technicians, and machine operators responsible for installation or service. Typical applications include industrial automation panels, conveyor systems, packaging equipment, HVAC controls, machine tools, and motor-control assemblies.

Correct sizing is essential. The transformer must support both the continuous VA load and the temporary inrush VA demanded when contactors, relays, or other inductive devices energize. Always verify the exact catalog number, wiring diagram, voltage ratings, terminal markings, certifications, and installation requirements before connecting power.

Allen Bradley 1497 Control Circuit Transformer Specifications

Product family: Allen-Bradley Bulletin 1497 control circuit transformers.
Electrical configuration: Single-phase transformer for industrial control circuits.
Primary voltage range: Product-family configurations span approximately 115 to 600 V AC; the exact range depends on the catalog number.
Frequency: Available configurations support 50 Hz, 60 Hz, or 50/60 Hz operation as identified on the nameplate.
VA capacity: Bulletin 1497 models are available in multiple ratings, including compact control-panel sizes and larger industrial ratings. Confirm the exact continuous VA rating on the product label.
Primary connections: Models may use single-voltage, dual-voltage, or multitap primary terminals.
Secondary output: Common control-voltage configurations include 24, 120, and other application-specific secondary voltages.
Construction: Selected models use epoxy-encapsulated transformer construction and protected terminal arrangements.
Protection options: Factory-installed or panel-mounted primary and secondary fuse blocks may be available on selected catalog numbers.
Selection benchmark: Choose a transformer whose inrush VA is equal to or greater than the calculated control-circuit inrush demand.
Compliance: Applicable approvals and ratings vary by model, installation region, and catalog configuration.

Never substitute a specification from one Bulletin 1497 model for another. Use the nameplate and the manufacturer’s technical documentation for final selection.

Detailed Description of the Allen Bradley Control Circuit Transformer 1497

The Allen Bradley Control Circuit Transformer 1497 operates through electromagnetic induction. Alternating current applied to the primary winding creates a magnetic field in the transformer core. This field induces a proportional voltage in the isolated secondary winding, allowing the control circuit to operate at a lower or otherwise appropriate voltage than the incoming supply.

Electrical isolation helps separate control wiring from the main supply circuit and can improve serviceability when the control circuit is properly fused and grounded. The transformer does not regulate voltage like an electronic power supply; its secondary voltage varies with input voltage, load, wiring, and transformer characteristics.

In day-to-day operation, technicians should inspect terminals, conductors, fuse holders, and ventilation clearances during scheduled maintenance. De-energize and lock out the equipment before cleaning or inspection. Remove dust with a dry, nonconductive method and keep moisture, oil, metal particles, and loose hardware away from the transformer.

Mounting hardware and enclosure materials depend on the specific version. Epoxy-encapsulated construction can help protect internal windings from industrial contamination, but it does not eliminate the need for correct overcurrent protection, adequate spacing, and environmental control.

How to Install and Set Up an Allen Bradley 1497 Transformer

Read the transformer nameplate and confirm the catalog number, primary voltage, secondary voltage, frequency, VA rating, terminal markings, and fuse requirements.
Calculate the control circuit’s continuous VA load and total inrush VA. Include contactors, relays, solenoids, pilot lights, timers, and other devices energized at the same time.
Select a mounting location inside a suitable enclosure with adequate clearance, ventilation, and access for wiring and inspection.
Install the transformer securely using the manufacturer-approved mounting method. Do not modify the core, enclosure, terminals, or mounting structure.
Connect the protective grounding conductor to the designated grounding point. Follow local electrical codes and the panel’s grounding scheme.
Install correctly rated primary and secondary overcurrent protection where required. Use the wiring diagram supplied for the exact model.
Connect the incoming supply to the correct primary terminals. For multitap models, use only the tap matching the measured supply voltage.
Connect the secondary circuit to the correct output terminals and verify polarity or control-circuit conventions where applicable.
Inspect every connection for correct torque, insulation clearance, conductor size, and absence of stray wire strands.
With personnel clear, energize the circuit and measure the secondary voltage before connecting sensitive control equipment.

Safety warning: Installation must be performed by qualified personnel. Lock out and tag out all energy sources before wiring. Never work on exposed terminals while energized.

Allen Bradley 1497 Transformer Troubleshooting Guide

Transformer has no secondary output

Disconnect power and check the primary disconnect, primary fuse, wiring, terminal selection, and supply voltage. Confirm that the selected primary tap matches the incoming voltage. A blown fuse may indicate a short circuit, excessive inrush, incorrect wiring, or an undersized transformer.

Secondary voltage is too low

Measure the primary voltage under load and compare it with the nameplate rating. Check for excessive control-circuit demand, long undersized conductors, loose terminals, or simultaneous inrush from multiple devices. A transformer selected only for continuous VA may fail to maintain adequate voltage during startup.

Fuse opens repeatedly

Inspect secondary wiring and connected loads for shorts or damaged insulation. Disconnect loads individually to identify the affected branch. Verify fuse type and rating against the exact catalog number and applicable electrical code; never install a larger fuse to prevent nuisance opening.

Transformer runs hot or hums

Some operating noise and heat are normal, but excessive temperature, odor, vibration, or discoloration requires immediate de-energization. Check for overload, incorrect frequency, overvoltage, restricted ventilation, loose mounting, or damaged windings.

Error codes and support

Bulletin 1497 transformers generally do not provide a digital display or standardized electronic error-code system. Troubleshooting therefore relies on electrical measurements, inspection, and the model-specific wiring diagram. Record the complete catalog number and manufacturing information before contacting Rockwell Automation support or an authorized distributor. Warranty coverage and service eligibility depend on the purchase channel, installation conditions, and applicable terms.

Pros and Cons of the Allen Bradley Control Circuit Transformer 1497

Advantages

Broad application range: Multiple primary, secondary, frequency, and VA configurations support machine controls, automation panels, and industrial equipment.
Flexible voltage selection: Selected versions offer dual or multitap primary connections for different supply systems.
Industrial construction: Epoxy-encapsulated options and protected terminals are suited to properly designed control panels.
Serviceable architecture: A conventional transformer design is straightforward to test with a multimeter and maintain with standard electrical procedures.
Protection options: Compatible models may include primary and secondary fuse-block arrangements.

Limitations

Model-specific selection: Voltage, VA, terminals, dimensions, and fuse provisions differ by catalog number.
No electronic regulation: Secondary voltage can change with supply variation and loading.
Inrush sensitivity: Incorrect sizing can cause startup voltage drop, nuisance fuse operation, or contactor chatter.
Installation expertise required: Primary circuits can present lethal voltage and require qualified installation.
Not always the best fit: A regulated switching power supply may be more suitable where precise DC voltage, compact size, or high efficiency is required.

The Allen Bradley Control Circuit Transformer 1497 is best suited to users who need robust, isolated AC control power and can match the transformer precisely to the machine’s voltage and inrush requirements.

PDF

Faqs

How do I set up the allen bradley Control Circuit Transformer 1497 for the first time?

First verify the complete catalog number, primary voltage, secondary voltage, VA rating, frequency, and fuse configuration on the nameplate. De-energize and lock out the incoming supply, mount the transformer securely, and connect the primary and secondary conductors to the terminals shown in the 1497 wiring diagram. Confirm that all unused taps are insulated, install required overcurrent protection, bond grounding conductors correctly, and inspect terminal tightness before applying power.

How can I choose the correct VA rating for an allen bradley Control Circuit Transformer 1497?

Add the sealed VA burden of every control device that may operate simultaneously, then account for the highest inrush VA from contactors, solenoids, relays, or motor starters. Select an Allen-Bradley 1497 transformer whose continuous VA rating meets the calculated sealed load and whose inrush capability supports the starting demand. Do not size only from the normal running current; insufficient inrush capacity can cause secondary-voltage drop, chattering contactors, or nuisance fuse operation.

What should I check if the allen bradley Control Circuit Transformer 1497 has no secondary output?

Begin by disconnecting power and checking the primary fuse, secondary fuse, disconnect device, and wiring for an open circuit. Verify that the applied primary voltage matches the selected 1497 primary connection and that the secondary terminals are correctly identified. Inspect for loose or damaged conductors, an overloaded control circuit, or a shorted downstream device. Never bypass a blown fuse; determine and correct the fault before replacing it with the specified type and rating.

Can I use any 1497 transformer with a 24 V or 120 V control circuit?

No. Bulletin 1497 includes multiple primary voltages, secondary voltages, VA ratings, frequencies, tap arrangements, and fuse options. Match the transformer nameplate to the control circuit requirements before installation. A 24 V secondary model cannot replace a 120 V model, and a transformer designed for a different primary connection may be damaged or produce an unsafe output. Confirm the exact catalog number, wiring diagram, frequency, and load requirements with the equipment documentation.

Why does my allen bradley Control Circuit Transformer 1497 produce a low or fluctuating control voltage?

Low secondary voltage can result from excessive inrush, an undersized VA rating, incorrect primary taps, low incoming voltage, loose terminals, or an overloaded control circuit. Measure the primary and secondary voltage both unloaded and while the controls operate. Compare the readings with the transformer nameplate and application requirements. Also inspect contactor coils and solenoids for abnormal current draw. If voltage falls only during starting, reassess inrush sizing rather than adjusting connections randomly.

How should primary and secondary fuses be selected for an allen bradley Control Circuit Transformer 1497?

Use the exact 1497 catalog number, nameplate data, applicable installation code, and the manufacturer’s technical documentation to determine fuse requirements. Primary and secondary protection serve different purposes, and some transformers include factory-installed fuse blocks while others require external protection. Choose the correct fuse class, voltage rating, interrupting rating, and ampere rating for the circuit. Confirm that the fuse arrangement protects both the transformer and connected control wiring without exceeding conductor limits.

What installation practices improve allen bradley Control Circuit Transformer 1497 performance?

Use conductors sized for the expected current and installation conditions, keep control wiring separate from noisy power conductors where practical, and tighten terminals to the specified torque. Provide adequate ventilation and avoid mounting the transformer where heat, moisture, vibration, or metal debris can accumulate. Minimize unnecessary secondary-circuit length to reduce voltage drop. Correctly identifying primary taps and keeping connections clean helps the 1497 deliver stable control power and reduces nuisance interruptions.

How do I maintain an allen bradley Control Circuit Transformer 1497 safely?

Schedule periodic inspections based on the machine environment and operating duty. After lockout and verification of zero energy, check for discoloration, overheating, unusual odor, vibration, damaged insulation, loose terminals, corrosion, and dust buildup. Inspect fuse holders and grounding connections, and review whether the connected control load has changed. Keep the transformer dry and clean using approved methods; do not spray liquid into the enclosure. Replace damaged components rather than operating a transformer with compromised insulation or terminals.