DIesel Generator

Sizing Calculator

Before using a power requirement calculator for generators, start by gathering key data. In the Philippines—where power interruptions, voltage fluctuations, and grid limitations can occur—accurate sizing is even more critical.

Answer these questions to ensure precise calculations:

What items will the generator power?

Make a complete list of all equipment that will run on the generator. This includes:

  • Air conditioning units (common in offices, malls, and hotels)
  • Elevators and escalators
  • Refrigeration systems (critical for restaurants, cold storage, groceries)
  • Lighting systems
  • IT equipment and servers
  • Industrial machines

Missing even a few items can lead to under-sizing, which may result in overloads or system failure during outages.

 In the Philippines, coordinate with your facility engineer or building administrator to ensure all loads—including critical and non-critical—are accounted for.


What is the starting and running wattage of those items?

Check the equipment nameplate or owner’s manual for:

  • Running watts (continuous load)
  • Starting watts (especially for motors, compressors, and pumps)

If documentation is unavailable:

  • Look up the model online
  • Contact the supplier or manufacturer
  • Use estimation charts (but treat them as approximations)

Many locally used equipment items (e.g., air conditioner units, pumps) have high starting currents, which is a major factor in generator sizing.


What is the total power requirement?

Once all loads are identified:

  • Convert everything into kilowatts (kW) or kilovolt-amperes (kVA)
  • In the Philippines, generators are commonly rated in kVA, so apply the formula:
    kW ÷ Power Factor (typically 0.8) = kVA

Example:
If your total load is 80 kW → Required generator ≈ 100 kVA


 

How to Calculate Your
Total Power Requirements

There are several methods commonly used by Philippine businesses:

1. Measure Peak Usage in Real-Time

Use a clamp meter (clamp-on ammeter) to measure actual current during peak operations.

  • Take readings during full-load conditions (e.g., midday for offices, dinner rush for restaurants)
  • Measure across all panels and sum the values

 This method is widely used by genset suppliers and contractors in the Philippines for accurate sizing.


2. Review Your Monthly Power Bills

Check your electricity bills from utilities like:

  • Meralco
  • VECO
  • Davao Light

Look for:

  • Peak demand (kW or kVA)
  • Highest recorded demand in the past 12 months

 Add 20–30% allowance to cover:

  • Future expansion
  • Sudden load spikes
  • Equipment startup loads

3. Estimate Based on Facility Type and Size

For quick estimates:

  • Offices / Hotels / Restaurants:
    ~5 watts per square foot + 50 kW baseline
  • Retail / Commercial Spaces:
    ~10 watts per square foot

 In the Philippine setting, adjust higher if:

  • Heavy air conditioning is used (common due to tropical climate)
  • Operations are 24/7 (e.g., BPOs, hospitals)

 

Important Variables
to Consider

Even with accurate calculations, local conditions matter:


Voltage Dips and Power Quality

After outages, equipment like motors and compressors draw high current.

  • Voltage dips beyond 15% can:
    • Damage sensitive equipment
    • Cause generator shutdown

This is especially relevant in areas with frequent brownouts or unstable grid supply.


Single-Phase vs. Three-Phase Power

  • Single-phase:
    Suitable for small offices, retail shops, and residential use
  • Three-phase:
    Required for:
    • Manufacturing plants
    • High-rise buildings
    • Large commercial facilities

\Most medium to large businesses in the Philippines operate on three-phase systems.

Philippine Electrical Code (PEC) Compliance

Instead of NEC, the Philippines follows the

  • Philippine Electrical Code

Ensure:

  • Life safety systems (fire pumps, alarms, emergency lighting) are included
  • Required standby or emergency loads are prioritized
  • Proper load segregation (essential vs non-essential)

Environmental and Operational Factors

  • High ambient temperatures (common in PH) can reduce generator efficiency
  • Fuel availability (diesel logistics during disasters or typhoons)
  • Noise regulations in urban areas (e.g., Makati, BGC)

Final Insight

In the Philippines, generator sizing is not just about computation—it’s about reliability under real-world conditions:

  • Frequent outages
  • High cooling demand
  • Critical 24/7 operations

That’s why many companies don’t rely on a single method—they combine calculations, actual measurements, and expert consultation to ensure the generator can handle both current and future demands.

CONTACT AN EXPERT NOW!

Kilton Bldg., #6 Golden Mile Avenue,
Golden Mile Business Park, Brgy. Maduya, Carmona, Cavite, Philippines

Tel Nos:
+63 2 8889 1023 / +63 2 8844 5032
+63 2 8736 3650 /  +63 2 8844 5031
Telefax: +63 2 8889 1023

Sales Hotline: (SMS, Viber, WhatsApp)
+63 961 780 2771

Services and Parts Hotline:
(SMS, Viber, WhatsApp)

+63 922 838 2034 +63 917 534 0474
+63 961 780 2771 +63 28664 9996

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Kilton Bldg., #6 Golden Mile Avenue, Golden Mile Business Park, Brgy. Maduya, Carmona, Cavite, Philippines

Tel Nos:
+63 2 8889 1023 / +63 2 8844 5032
+63 2 8736 3650 /  +63 2 8844 5031 Telefax: +63 2 8889 1023

Sales Hotline: (SMS, Viber, WhatsApp)
+63 961 780 2771

Services and Parts Hotline: (SMS, Viber, WhatsApp)
+63 922 838 2034 +63 917 534 0474
+63 961 780 2771 +63 28664 9996

Resource Center

Gallery

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