The electrical cabinet is the central nervous system of every roll forming machine. Inside it, PLCs, VFDs, servo drives, relays, power supplies, contactors, and safety circuits all work together to keep production running smoothly. When an electrical cabinet develops faults, even the smallest issue can shut down the entire machine — leading to missed delivery deadlines, inaccurate panels, and expensive downtime.

This guide explains the most common electrical cabinet faults, their causes, symptoms, and the exact troubleshooting steps required to get your roll forming line back in operation quickly and safely. It applies to all machine types: roofing, purlin, decking, light-gauge frame, tube mill, flashing, guardrail, and more.

Machine Matcher provides full electrical technician services worldwide, including cabinet rewiring, panel diagnostics, component replacement, and 24/7 remote support.

1. Why Electrical Cabinet Faults Are So Critical

Electrical cabinets on roll forming machines control:

• Motors and motor protection

• PLC logic and sequencing

• Hydraulic valves and solenoids

• Punch timing

• Flying saw synchronisation

• Length measurement

• Servo positioning

• Safety circuits

• Sensors and encoder feedback

When something goes wrong inside the cabinet, entire machine systems fail — even if all mechanical components are perfect.

2. The Most Common Electrical Cabinet Faults

Below are the top electrical cabinet issues seen on roll forming machines worldwide.

2.1 Loose or Burnt Terminals

Causes

• Machine vibration

• Poor wiring practices

• Overloaded circuits

• Heat expansion

• Loose neutral or ground

Symptoms

• Intermittent faults

• Random machine stops

• Sensor flickering

• Motor overload trips

• VFD undervoltage alarms

Fix

• Tighten all terminals

• Replace burnt connectors

• Measure voltage drop under load

• Check torque specs for terminals

2.2 Overheating Inside the Cabinet

Causes

• Blocked air vents

• No cooling fans

• High ambient temperature

• VFD or servo overheating

• Excessive dust buildup

Symptoms

• VFD OH faults

• PLC resets

• Power supply shutdown

• Communication errors

• Melted wiring insulation

Fix

• Install cooling fans & filters

• Clean cabinet

• Add thermal relays

• Improve ventilation in factory

2.3 Faulty 24VDC Power Supply

This is responsible for 40–60% of all electrical faults in roll forming machines.

Causes

• Cheap power supply

• Overloaded output

• Weak grounding

• Heat damage

Symptoms

• Sensors flicker ON/OFF

• PLC input instability

• Encoder pulse loss

• Output solenoids fail randomly

• PLC restarts

Fix

• Replace power supply

• Measure voltage under load

• Separate sensor and coil loads

• Ground power supply correctly

2.4 Contactor and Relay Failures

Causes

• Worn contacts

• Coil burnout

• Heat damage

• Poor-quality components

Symptoms

• Motors won’t start

• Valves fail to energize

• Machine runs intermittently

• Panel makes “chattering” sound

Fix

• Replace contactor or relay

• Check coil voltage

• Verify output from PLC

2.5 VFD & Servo Drive Failures Inside Cabinet

Causes

• Heat

• Line voltage issues

• Incorrect parameters

• Output short circuits

• EMI/Noise

Symptoms

• OC / OV / UV faults

• Flying saw sync errors

• Motor speed instability

• Overload trips

Fix

• Inspect wiring to drives

• Test output phases

• Verify grounding & shielding

• Restore correct parameters

2.6 Damaged or Poor-Quality Wiring

Causes

• Cheap wires

• Incorrect sizing

• Oil contamination

• Rodents/insects

• Cable rubbing on metal edges

Symptoms

• Random I/O faults

• Shorts to frame

• Burnt insulation

• Flickering signals

Fix

• Replace damaged wires

• Add trunking or conduit

• Secure with cable ties

• Label all wiring correctly

2.7 Incorrect Grounding & Shielding

Grounding problems create noise, which leads to:

• Encoder misreads

• Flickering sensors

• Servo jitter

• Communication loss

Fix

• Bond all grounds to a common point

• Add shield clamps

• Use proper grounding bars

3. Electrical Cabinet Safety Issues

Electrical cabinets also contain critical safety circuits:

• Safety relays

• E-stop loops

• Door interlocks

• Overload relays

• Thermal sensors

Faults in these systems can:

• Prevent startup

• Cause unexpected shutdowns

• Create hazardous conditions

• Disable machine protection

Machine Matcher offers full safety-circuit auditing and certification.

4. Step-by-Step Troubleshooting Procedure

Step 1 — Visual Inspection

• Burnt smell?

• Melted wires?

• Loose components?

• Dust buildup?

• Overheated drive?

Step 2 — Check Power Supplies

• 24VDC

• 5VDC (encoder systems)

• 230–460VAC 3-phase

Step 3 — Test Inputs & Outputs

Use PLC monitor mode to check:

• Sensor feedback

• Limit switch state

• Output commands

Step 4 — Inspect VFD/Servo Parameters

• Check fault history

• Confirm motor data

• Verify encoder settings

Step 5 — Check Motor Circuits

• Overload relays

• Thermal sensors

• Contactor function

Step 6 — Inspect Grounding & Shielding

• Earth faults

• Noise issues

• Encoder shielding

Step 7 — Tighten and Label Everything

A well-organized panel prevents 90% of future issues.

5. Preventing Electrical Cabinet Failures

✔ Clean cabinets regularly

✔ Tighten terminals quarterly

✔ Replace worn components proactively

✔ Use high-quality power supplies

✔ Avoid mixing signal and power wires

✔ Install proper cooling

✔ Keep a parameter backup (PLC/VFD/servo)

✔ Schedule yearly cabinet inspections

Machine Matcher provides preventive maintenance plans customized for your machine type, production volume, and region.

6. When to Call an Electrical Technician

You need professional help if you experience:

• Frequent VFD trips

• Flickering PLC inputs

• Cabinet overheating

• Repeated sensor/encoder faults

• Electrical burning smell

• Motor circuit failures

• Unsafe wiring

• Emergency shutdowns

• Control panel errors

Machine Matcher provides:

• Electrical cabinet rewiring

• Panel upgrades

• PLC/VFD/servo diagnostics

• Thermal scanning

• Safety circuit certification

• 24/7 remote troubleshooting

• On-site repairs worldwide

7. FAQ — Electrical Cabinet Troubleshooting

Q1: Why is my electrical cabinet overheating?

Blocked vents, dust buildup, or failing fans.

Q2: Why does my machine stop randomly?

Loose terminals or weak power supply.

Q3: Why does my PLC restart?

24VDC instability or electrical noise.

Q4: Why do my VFDs keep tripping?

Heat, overcurrent, or wiring issues.

Q5: Should I rewire the entire cabinet?

Yes, if wires are burnt, corroded, or poorly installed.

Conclusion

The electrical cabinet is the core of your roll forming machine — and when it fails, production stops instantly. Machine Matcher’s Electrical Technician Service provides the expert diagnostics, repairs, rewiring, and preventive maintenance needed to ensure your panel operates reliably, safely, and efficiently.

We support all machine types, all brands, and all global regions.

Reliable machines. Reduced downtime. Better production.
Machine Matcher delivers it.

Machine Matcher now offers full electrical technician services for roll forming machines — including diagnostics, rewiring, testing, encoder calibration, PLC programming, electrical audits, and preventive maintenance.
We support all machine types and all global regions.
Contact us today for immediate technical assistance or to schedule a full electrical inspection at your factory.

Looking for the right roll forming machine or expert guidance on your next project? Machine Matcher is here to help. Our global team provides 24/7 technical support, expert advice, and guidance on machine selection, setup, and maintenance—ensuring your operations run smoothly from day one.

With team members based worldwide—including the UK, USA, Middle East, and beyond—we are equipped to assist buyers across the globe. Whether you’re sourcing a single machine or upgrading an entire production line, our experts are ready to provide tailored solutions and support every step of the way.

Get in touch now and let Machine Matcher help you find the perfect roll forming machine for your business.

United Kingdom (Main Office)
Phone: +44 20 335 56554

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Phone: +1 407 559 7948

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Email: [email protected]