Deep Sea Electronics · DSE 8000 Series (Mains/ATS Control)

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DSE 8660 MkII

Controllers

Auto transfer switch and mains control module for multi-generator paralleling systems. Manages utility sync, no-break transfer, and mains decoupling protection.

Overview#

The DSE 8660 MkII is an auto transfer switch and mains control module — the utility-side controller in a DSE-based multi-generator paralleling system. While the DSE 8610 MkII manages individual generators (one per genset), the 8660 manages the mains/utility connection: monitoring power quality, commanding sync/transfer operations, and providing critical safety functions like mains decoupling protection.

Every DSE-based paralleling installation needs exactly one 8660 (for the mains connection) plus one 8610 per generator.

The paralleling system architecture#

Utility → [DSE 8660 MkII] → Mains Bus
                                   ↕ (DSENet communication)
Generator 1 → [DSE 8610 MkII] → Gen Bus ─┐
Generator 2 → [DSE 8610 MkII] → Gen Bus ─┤→ Common Bus → Load
Generator 3 → [DSE 8610 MkII] → Gen Bus ─┘

The 8660 decides:

Key capabilities#

Our service experience#

We configure and maintain DSE 8660-based paralleling systems at hospitals and data centers where N+1 redundancy with utility tie is required. The 8660's mains decoupling protection is the critical safety function — it must detect utility loss within cycles and island the generators before backfeed occurs. During annual maintenance, we test this protection by simulating mains loss and verifying the system islands correctly, then verifying no-break return-to-mains when utility is restored. The DSE Configuration Suite programs both the 8610s and 8660 from one software interface.

Frequently Asked Questions

What does the DSE 8660 do?
The 8660 is the mains-side brain of a paralleling system. It monitors utility power, decides when to sync generators to mains (or island from mains), manages no-break transfer, and provides mains decoupling/export protection. It does NOT start engines or control generators directly — that's the DSE 8610's job.
How do the 8610 and 8660 work together?
A typical paralleling system has: one DSE 8660 MkII (mains controller) + one DSE 8610 MkII per generator. The 8610s manage individual gensets (start/stop, speed, voltage, load sharing). The 8660 manages the mains connection (utility monitoring, sync decisions, transfer commands, decoupling protection). They communicate via DSENet.
What is no-break transfer?
No-break (closed transition) transfer means generators synchronize with the utility before the transfer switch operates — so the load never sees an interruption. The 8660 manages the synchronization timing: it holds the transfer switch until voltage, frequency, and phase angle are matched, then commands the changeover. This is essential for hospitals and data centers.
What is mains decoupling protection?
If the utility fails while generators are paralleled with mains, the 8660 detects the loss-of-mains condition and immediately opens the mains breaker to 'island' the generators. This prevents generators from backfeeding into a dead utility grid (dangerous for utility workers) and protects generators from re-sync shock when utility returns unexpectedly.
Can one system have multiple mains connections?
Yes — with additional DSE 8660 modules, a system can monitor multiple utility feeds (normal + alternate) and manage complex transfer schemes between them. This is common in facilities with dual-utility-feed redundancy.

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