Generator Sizing Guide

Onsite Estimating Sheet

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Job Name _____________________________________________

Date___________ Location _______________________________

VOLTAGE

120/240 1Ø

120/208 3Ø

277/480 3Ø

TYPE

Natural Gas

LP Vapor LPV)

 

ELEC. SERVICE

100 Amp

200 Amp

400 Amp

 

600 Amp

Other________

 

Before installation contact local jurisdiction to confirm all requirements are met. Jurisdictions may vary. Siemens recommends contacting local authorities prior to installation.

Loads: Look for heavy building loads such as refrigeration, air conditioning, pumps or UPS systems.

Use the following for sizing and determining generator kW.

Table 6

Motor Load Table (refer to Table 1)

Device

HP

RA

LRA

kW Running

Starting

 

 

 

 

(= HP)

kW

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Starting kW for HP < 7.5 starting kW = HP x 3 Starting kW for HP > 7.5 starting kW = HP x 2

Starting kW for loading with no listed HP, calculate HP based on running amps in the chart on the right.

Table 7

Non-Motor Load Table (refer to Table 2)

Device

Amps

kW

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

QT Upgrade Required

These applications require an upgrade from the QT Series: NEC 695 Fire Pumps

NEC 700 Emergency Systems NFPA 20 Fire Pumps

NFPA 99 Healthcare

NFPA 110 Emergency Systems

Reference Codes

Related Codes and Standards:

NEC 225 Branch Circuits and Feeders

NEC 240 Overcurrent Protection

NEC 250 Grounding

NEC 445 Generators

NEC 701 Legally Required Standby

NEC 702 Optional Standby

NFPA 37 Installation and Use of Stationary Engines

NFPA 54 National Fuel Gas Code

NFPA 58 LP Gas Code

To Calculate kW (refer to page 2 for shortcut)

120 V 1Ø

Amps x 120/1000 = kW

240 V 1Ø

Amps x 240/1000 = kW

208 V 3Ø

Amps x 208 x √3 x PF/1000 = kW

240 V 3Ø

Amps x 240 x √3 x PF/1000 = kW

480 V 3Ø

Amps x 480 x √3 x PF/1000 = kW

PF is application power factor (worst case 1.0)

Typical application power factor is 0.95.

Resources in Sizing Guide

Surge Capability Chart – References running amps of units and LRA Propane Tank Sizing Chart – Measures fuel consumption of generator units Motor Load Reference Guide – Reference guide for basic motor loads Non-Motor Load Reference Guide – Reference guide for non-motor loads Fuel Piping Sizing Chart – Assists in calculating adequate pipe size for natural gas and propane

UPS – Generator Compatibility

UPS Information

1.5 x kVA rating for a filtered system

3 – 5 x kVA rating for an unfiltered system

Siemens recommends you refer to the Siemens UPS Generator Compatibility sheet and notify the manufacturer of the UPS system to assist in your installation.

Transfer Switch Availability

SR6ST – 100 and 200 Amp service entrance rated

RTS – 100, 200, 400 Amp

SR6SI switch only works with R100 controller.

XT 6XR – 100, 150, 200, 300, 400, 600, 800 Amp

HTS switch only works with H100 controller. Avail. in NEMA 1, NEMA 3R and NEMA 12. Refer to Siemens product catalog for the appropriate transfer switch.

Recommended Generator Size ________ Refer to Generator Sizing Instructions on other side of this sheet.

INSTALL NOTES:

1.Suggested concrete pad minimum thickness of 4" with 12" overhang on all sides. Fiberglass pad included with air-cooled products.

2.Consult manual for installation recommendations.

3.Consult local authority having jurisdiction for local requirements.

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Siemens Standby Generators manual Onsite Estimating Sheet

Standby Generators specifications

Siemens Standby Generators provide reliable power solutions for both residential and commercial applications, ensuring that homes and businesses remain operational during power outages. These generators stand out due to their advanced engineering, innovative technology, and robust design, making them a preferred choice for those seeking uninterrupted power.

One of the primary features of Siemens standby generators is their automatic transfer switch (ATS) capability. This technology allows for seamless switching from the utility power source to the generator within seconds of a power outage. The ATS continuously monitors the incoming utility power and activates the generator when it detects an interruption. This ensures that critical appliances and systems remain functional without manual intervention.

In terms of performance, Siemens generators are equipped with continuous power ratings that cater to varying power needs. Whether it’s an essential load or a full-scale home or commercial operation, these generators can handle the demands efficiently. Most models come with powerful engines, designed for durability and longevity, ensuring they can operate under heavy loads without compromising performance.

Siemens also employs advanced noise reduction technologies in their standby generators, which significantly reduce operational noise levels. This feature is particularly beneficial for residential areas where noise compliance is essential. Additionally, the generators are engineered with vibration dampening systems, enhancing user comfort and ensuring minimal disturbance to the surrounding environment.

The fuel efficiency of Siemens generators is another remarkable characteristic. Many models utilize propane or natural gas, allowing for cleaner and more sustainable operation compared to traditional diesel generators. These fuel types not only reduce emissions but also lower operational costs over time, making Siemens generators a more economical choice for long-term power solutions.

Moreover, Siemens generators are designed with user-friendly interfaces and smart monitoring systems. Users can track generator performance, maintenance schedules, and fuel levels through digital displays or smartphone applications. This connectivity allows for proactive maintenance, reducing the risk of unexpected failures and ensuring that the generator remains in optimal working condition.

In summary, Siemens Standby Generators combine reliability, efficiency, and advanced technology to deliver unparalleled performance during power outages. With features such as automatic transfer switches, low noise operation, fuel efficiency, and smart monitoring, they provide users with peace of mind and a steady power supply whenever needed. Whether for residential or commercial use, Siemens generators are a trusted solution for maintaining essential services and comfort in the face of power interruptions.