When space is at a premium and reliability is critical, Generac’s Gemini® power system is the answer. An option of Generac’s Modular Power System (MPS), the Gemini features two 500 kW generators connected in parallel within a single enclosure.

1 MW of Power in a Small Space
Gemini combines the output of two 500 kW generators packaged inside a single enclosure using Generac’s exclusive PowerManager™ control system. The result is 1 MW of power in a space up to 40% smaller than a large, single engine genset.

Fast Turn-around Time
By using smaller, high-volume industrial diesel-fueled engines, Gemini gensets can normally be delivered weeks or even months faster than a large single-engine unit.

Easy Serviceability
The Gemini generator engines can be serviced by any qualified diesel technician using commonly available parts.

Up to 7 MW as Part of a MPS
Up to seven Gemini gensets can be paralleled without additional switchgear, for a total output of up to 7000 kW. Invest in the power you need today, and expand in the future as necessary.

Critical Load Redundancy
Gemini’s load shedding capability ensures that critical loads are covered even if one of the units is offline for maintenance.

Standby Emergency Generators

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What is a Gemini system comprised of?
Two diesel 500 kW gensets in a single enclosure. Up to seven Gemini units can be paralleled for a total output of 7000 kW.

Must all of the gensets in a system have the same kW rating?
Individual gensets with different kW ratings can be used within a single system. The only exceptions are the MQT gensets which can only be paralleled with other MQT units with the same kW rating.

What kind of paralleling switchgear is required for an MPS system?
Generac MPS is a completely integrated system, so no additional switchgear is needed. Our PowerManager® Digital Control Platform features a 32-bit microprocessor and replaces multiple generator controllers and expensive paralleling switchgear. The PowerManager G-Series is a flexible control platform that utilizes mission-specific software that enables it to function as the controller for the individual gensets, an integrated paralleling controller and the system controller.

How does MPS facilitate internal and external communications?
The PowerManager G-Series features integrated PLC functions and numerous I/Os that make it easy to customize controls and link directly with facilities management systems. Two Modbus RS 485 ports accommodate controller-to-generator and controller-to-annunciator or building management system communications. An integrated Ethernet modem with an RS232 port provides remote computer interface and control using our GenLink® software.

What happens if one of the gensets does not start or is lost after transfer?
The PowerManager System G-Series System Controller has ATS permissive relays. If the loads are prioritized among two or more transfer switches, the permissive controls will not allow lower priority loads to switch to emergency power and the critical load is automatically spread among the remaining gensets. If transfer has already occurred, lower priority loads are immediately shed and the critical load is carried by the remaining gensets.

How many automatic transfer switches can be used in a single system?
There is no limit on the number of open transition, closed transition or bypass isolation switches that can be used within a system. Only one soft load switch can be used.

Can the G-Series System Controller interface with third party transfer switches?
Yes, provided that the switches have a two-wire start, can be mechanically held in the neutral position by the controller for load shedding and can be inhibited by the controller from switching to the emergency position until adequate generator power has come onto the generator bus.

Do all of the gensets have to be placed together?
No. Generac MPS gensets can be separated to allow you to better utilize available space. It is possible to place some units on the ground and others on the roof, or to utilize multiple smaller spaces without affecting performance. The location of the system controller is limited to no more than 1500 feet by the RS-485 communication cable.

Are Modular Power Systems being used in mission critical applications?
Yes, these systems are fully compliant with NEC 700 and NFPA 110. Mission critical applications represent a significant percentage of MPS installations.

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