FAQs

Power Factor Correction is the process of improving the power factor of an electrical system—typically by reducing the phase difference between voltage and current—so that power is used more efficiently. Power factor is the ratio of real power (used to do work, measured in kW) to apparent power (total power supplied, measured in kVA).

PFC is needed when the power factor of a system is significantly less than 1 (typically below 0.95). This often occurs in facilities with lots of inductive loads like motors, pumps, HVAC systems, or fluorescent lighting. Low power factor results in:

• Higher energy costs due to utility penalties.
• Increased electrical losses.
• Overloaded equipment or reduced system capacity.

• Reduces electricity bills (especially demand charges)
• Frees up capacity on the electrical system, particularly in transformers & cables
• Improves efficiency by reducing losses in cables and transformers
• Enhanced equipment lifespan: Less strain on electrical components.
• Improves voltage regulation
• Helps meet utility compliance for power factor thresholds

PFC works by adding capacitors to the electrical system. These capacitors supply reactive power (kVAr) to counteract the inductive effects of certain loads, thus improving the overall power factor.

Understanding the difference between plain and detuned Power Factor Correction is crucial for safe and effective power quality management, especially in environments with harmonic-rich loads.

• Plain PFC involves connecting capacitor banks directly to the power system to supply reactive power and improve power factor.
• Use Case: Suitable for clean power environments with minimal harmonic distortion. Typically used in small-to-medium systems with linear loads (motors, HVAC, etc.).
• Risks: Resonance risk when harmonic-producing loads (like VFDs, UPS) are present. Capacitor damage and potential system instability due to amplification of harmonic currents.
• Detuned PFC includes series reactors (inductors) with the capacitor banks to shift the resonant frequency away from typical harmonic frequencies (e.g., 5th, 7th).
• Use Case: Designed for harmonic-rich environments (plants with VFDs, soft starters, computers, etc.). Prevents the capacitors from becoming a resonant trap for harmonics.
• Benefits: Protects capacitors from harmonic overload. Improves system stability and ensures safe reactive power compensation. Helps maintain compliance with IEEE 519 or similar standards.

Rule of Thumb: If your system includes non-linear loads, always use detuned PFC to avoid costly failures or harmonic amplification. If you have a lot of non-linear loads, then you may need to consider an Active Harmonic Filter.

An Active Harmonic Filter is a power electronic device that monitors the harmonics in an electrical system and dynamically cancels them out in real time using inverter-based technology.

AHFs are needed when there is a significant level of harmonic distortion in the power system, typically due to non-linear loads like variable speed/frequency drives (VSDs or VFDs), UPS systems, LED lighting, and switch-mode power supplies. In some situations, de-tuned PFC alone is not sufficient to manage harmonics—particularly where sites have sensitive equipment requiring clean power (e.g. medical devices, data centres, specialist manufacturing equipment)

An AHF works by:

• Continuously monitoring the electrical network & analysing the harmonic content.
• Generate counteracting currents (180° out of phase) to cancel harmonics.
• Inject these currents into the system, leaving only the fundamental 50/60 Hz waveform. AHFs can also correct power factor and balance loads in some cases.
• Injecting counter-phase current to neutralize harmonic components—this is done using fast-switching IGBT-based inverters.

Power Factor Correction (PFC) is great for improving displacement power factor caused by inductive loads like motors. However, it doesn’t address harmonics generated by nonlinear equipment such as VFDs, LED lighting, or UPS systems. Active Harmonic Filters (AHFs) not only improve power factor but also eliminate harmful harmonics that PFC capacitors can’t handle – and may even worsen. If your system includes modern electronic loads or suffers from voltage distortion or high THD, an AHF is the better, more comprehensive solution.

We supply a wide range of capacitors, including:

• Power Electronics & PFC capacitors
• AC/DC polypropylene film capacitors
• Electronicon-branded and custom-made units
• Suitable alternatives for obsolete or hard-to-source models

We offer the full Electronicon range:

• DC capacitors (E67, PK16, E80, E61)
• High-voltage box-type (E57, E59, SR17)
• General-purpose film capacitors (E51, E53, E55)
• Heavy-duty AC capacitors (E62, E64)

We hold stock of commonly used models for quick dispatch. For special or custom capacitors, lead times may vary—our sales team will confirm availability and delivery schedules based on your project needs.

Yes. We can provide reliable alternatives based on availability & technical fit. Our team can help select the best capacitor for your specific project needs.

Yes, our pricing depends on the order quantity, stock availability, and any minimum order requirements (MOQs). We offer competitive prices for both single units and bulk orders. Simply send us your specifications and quantity, and we’ll provide a tailored quote to suit your needs.

Yes, we specialize in providing capacitors tailored to your unique project needs. Whether you require custom specifications, special ratings, or specific designs, our team works closely with you to deliver the ideal solution that meets your application’s technical and performance demands.

We’ll help you choose based on:

• Application type (e.g., DC link, PFC, smoothing)
• Voltage and capacitance needs
• Current and frequency requirements
• Environmental and industry-specific conditions

Visit our Contact page or reach out via email or phone. Provide the requirement or part number (e.g., Electronicon part no E62.C58-102E10) and we’ll send datasheets, pricing, lead times.

Servicing helps identify issues like unnoticed capacitor failures that can lead to increased reactive power charges and potentially catastrophic failures if left unchecked.

It is recommended to service your Power Quality equipment annually.

Power Capacitors Ltd engineers perform a 56-point check, including environment, load, and suitability checks, and interrogate the relay to assess capacitor usage.

• Avoids unexpected reactive charges.
• Prevents equipment failures.
• Reduces the need for costly call-outs.
• Ensures optimal system performance.

Yes, they can maintain and service all makes of Power Quality equipment.

Power Capacitors offers a consolidated service:

• One supplier account
• One site induction
• One visit per site
• One invoice
• This saves time and administrative effort.

Yes, full service and equipment history is recorded and managed by Power Capacitors.

Yes, a fixed price service contract over 5 years is offered. It includes automatic service reminders and no upfront costs – invoicing is done after each service.

Power Capacitors Ltd has over 50 years of experience and operates the largest team of Power Quality engineers in the UK.

It depends on the size and complexity of your site. Smaller systems or simple troubleshooting checks can often be done in a few hours, while larger industrial setups may take a few days for a full, detailed assessment. We’ll chat through your requirements first and give you a clear time estimate before we start.

Just click the ‘BOOK A SURVEY’ or ‘REQUEST CALLBACK’ button on this page and we’ll get back to you to arrange a visit asap.

A Power Quality Survey will reveal the health and stability of your electrical system. It can reveal issues that may not be obvious but can lead to inefficiency, equipment damage, or downtime. See full list above.

There’s no one-size-fits-all answer – it really depends on how critical your systems are, how sensitive your equipment is, and whether you’ve experienced any power quality issues in the past.

At Power Capacitors, we usually recommend:

After major changes: If you’ve had a new installation, a big upgrade, or a major electrical event like an outage or equipment failure, a survey is the best way to check everything is running smoothly and up to standard.

For sensitive equipment: Facilities that rely on highly sensitive electronics or consistent power quality may need to be checked every year, or even more often.

As part of your maintenance plan: For most businesses, a full survey every 1-2 years is enough to catch potential problems before they turn into major problems.

Every site is different, so the ideal schedule is best set after a quick risk assessment and a chat with our experts. We’ll help you find the right balance to keep your power reliable and your operations running without a hitch.

A G5/5 survey is usually done before installing new equipment to check that your site will meet UK grid standards for harmonic emissions and gain approval from your network operator. A harmonic load survey is carried out on an existing system, measuring real-world harmonic levels to spot issues and recommend fixes if needed.

A surge protection device (SPD) is a piece of electrical safety equipment that safeguards your power system and sensitive electronics from damaging voltage spikes or power surges. Events such as lightning strikes, grid switching, or electrical faults can cause sudden overvoltages that damage machinery, IT systems, or building management controls. Installing a high-quality surge arrestor like PowerSoak helps prevent costly downtime and equipment replacement.

Yes, most businesses rely on electronic control systems, computers, and automated machinery that are highly sensitive to voltage fluctuations. A single mains-borne surge can cause data loss, breakdowns, or complete system shutdowns. Our PowerSoak industrial surge protector is a cost-effective solution that reduces these risks and helps ensure business continuity.

PowerSoak is designed as a robust, Type 2 surge protection solution that’s easy to integrate into existing electrical distribution networks. It offers <1kV protection level, 20kA nominal discharge current, and 50kArms short-circuit withstand, providing reliable protection for critical systems. Unlike many imported units, PowerSoak is manufactured in the UK by Power Capacitors Ltd, backed by over 50 years of expertise in power quality solutions.

Yes. The PowerSoak SPD is available in 3-wire and 4-wire models, making it suitable for both TNC and TNS earthing systems commonly used in UK and European industrial and commercial installations. Our specialists can recommend the best surge protection setup for your building or site.

In most cases, installing a PowerSoak Type 2 surge protection device provides strong, practical protection without requiring multiple devices. However, in environments with high exposure to lightning or highly sensitive electronics, a coordinated surge protection strategy (Types 1, 2, and 3) may be recommended. We offer free surge protection consultations to help you design the right solution for your facility.