Voltage Spikes: Their Impacts and How to Mitigate Them

Voltage spikes that exceed an electrical heater’s rated voltage can significantly shorten its lifespan by inducing a variety of harmful effects on the heater’s components. Failures originating from this root cause are some of the most difficult to identify. Often, the failure will come on with no warning and within a recipe that’s been used for years. It can take down a single heater or multiple heaters. Although it is not always the case, this type of issue is more prevalent in older facilities that may be utilizing older electrical systems and infrastructure. When you experience a mystery failure, the data acquisition records are a great place to start to check the supply voltage to the affected area.

Impacts of Voltage Spikes

1. Overheating Due to Excessive Voltage

Heaters typically consist of resistive elements (e.g. metal alloys such as Nichrome) that convert electrical energy into heat. The power dissipated by the heater is proportional to the square of the voltage (P = V² / R, where P is power, V is voltage, and R is resistance).

• • • Impact of voltage spikes: A voltage spike that exceeds the heater’s rated voltage will cause an increase in the power dissipated in the resistive heating element. Since power increases quadratically with voltage, even a small overvoltage can result in a large increase in temperature.
    • Thermal stress: This rapid and localized increase in temperature can cause the heater’s resistive element to overheat, which may lead to premature aging of the material. Over time, this thermal cycling can cause the metal to oxidize, embrittle, or even break, reducing the overall lifespan of the heating element.

2. Insulation Breakdown

Most electrical heaters are insulated with materials, such as ceramic or fiberglass, to prevent short circuits and protect the surrounding environment. The insulation is designed to withstand specific voltage ratings; exceeding these ratings can lead to:

• • • Dielectric breakdown: A voltage spike that exceeds the insulation material’s breakdown threshold can result in partial discharge or complete breakdown of the insulation. This can cause arcing, shorts, or even fire hazards, further compromising the heater’s safety and longevity.
    • Degradation of insulation: Repeated voltage spikes can accelerate the aging of insulation materials. The insulation may degrade due to heat, ionization, or physical damage caused by electrical arcing. This degradation makes it easier for faults like short circuits to occur, which will ultimately reduce the heater’s effective life.

3. Stress on Internal Components

Electrical heaters may include various components such as thermistors, thermostats, and control circuitry. These components are often designed to operate within certain voltage limits. Excessive voltage can affect these components in several ways:

• • • Overvoltage damage to control circuitry: The control electronics that manage the heater’s operation may be sensitive to voltage spikes. These components are typically designed with voltage regulators, but excessive spikes can overwhelm these protective measures and lead to component failure. For instance, capacitors or semiconductor devices (like diodes and transistors) may become damaged, causing the failure of the heater’s control system.
    • Faster wear of electronic components: Even if the heater doesn’t fail immediately, repeated voltage spikes can degrade the performance of semiconductors or other sensitive control elements. This can result in erratic operation, reduced efficiency, and, over time, component failure.

4. Mechanical Stress from Rapid Thermal Cycling

Voltage spikes often cause rapid, sudden increases in temperature in localized areas of the heater, leading to mechanical stress:

• • • Thermal expansion and contraction: The rapid heating and cooling cycle that occurs during a voltage spike lead to mechanical strain due to the differing rates of thermal expansion between materials in the heater (e.g. the heating element and the surrounding metal casing). Over time, this can cause fatigue in materials, leading to cracks or breaks in the heating element, especially if the spike is frequent.
    • Deformation of heaters: In extreme cases, repeated high-voltage events may cause warping or deformation of the heater structure, further compromising the function and integrity of the unit.

If the voltage spike is high enough, it may cause electrical arcing. This occurs when the voltage causes the air (or other dielectric medium) between contacts or along a surface to ionize, leading to an uncontrolled flow of electricity across a gap.

• • • Internal arcing: If the voltage spike is large enough, internal arcing can occur between elements inside the heater, which can erode conductive pathways or generate heat that further damages components.
    • External arcing: External arcing could also occur at connectors, leading to potential fire hazards or further deterioration of the electrical connections, resulting in reduced performance and potential failure of the heater.

6. Long-Term Effect of Repeated Spikes

Even if a single spike doesn’t cause immediate failure, repeated exposure to voltage spikes can cumulatively degrade the heater’s performance. Over time, this:

• • • Accelerates material aging: Repeated exposure to excess voltage stresses the resistive elements, insulation, and control electronics, leading to accelerated aging.
      • • • Reduces Efficiency: As components degrade, the heater may become less efficient. For instance, a damaged resistive element may have a lower resistance, resulting in reduced heating capacity or increased power consumption.
        • Increases Maintenance Costs: As the heater components fail or degrade, more frequent repairs or replacements may be necessary, increasing operational and maintenance costs.

• • • To minimize the impact of voltage spikes on heaters, several strategies can be employed. For example: surge protection. Surge protectors can be used to limit the effect of voltage spikes by clamping high voltages and preventing them from reaching the heater.
    • Overvoltage Protection Circuits: Use of varistors (MOVs), transient voltage suppressors (TVS), or other protective components in the heater’s power supply circuit can help absorb or divert excess voltage.
    • Design Adjustments: Heaters can be designed with wider voltage tolerance ratings and more robust insulation materials that can handle occasional spikes without degradation. Backer Marathon has extensive experience in this area. Contact a sales engineer now to discuss.

Voltage spikes that exceed the rated voltage of an electrical heater can lead to overheating, insulation breakdown, stress on internal components, mechanical damage, and arcing. These effects reduce the efficiency and lifespan of the heater and can cause safety hazards. Protecting against these spikes is crucial for maintaining the heater’s long-term reliability and safety. Backer Marathon’s process heating team is ready to discuss any of these concerns with you.

Why Backer Marathon

Backer Marathon is the industry leader in production speed, and reliable, quality heaters for plastics and packaging, serving OEMs with durable, customized solutions for unique heating needs since 1996. We design, manufacture, and stock industrial-grade heating elements and temperature sensors. Engineers have live, on-demand access via phone to our trained technical experts who have been pioneers in this sector for decades.

How can Backer Marathon’s experts help you today? Nosotros hablamos español. Contact us today to discuss your next project.