One Device, Four Functions: ODES WTM32 Simplifies Manual Synchronizing Wiring

TonyZhang
Jan 18
5 min read

Manual Synchronizing Deserves Better Than “Four Boxes and a Wiring Maze”

On a manual synchronizing panel, the operator has to do two things at the same time:

See both sides – voltage, frequency and phase angle
Decide whether it is safe to close the breaker

In many existing cabinets this means a whole chain of devices:

Synchroscope (synchronizing meter)
Synchro-check relay
Phase-angle transducer (“angle shifter”)
Isolation transformer(s)

The result is long wiring runs, many terminal levels, multiple error sources, and a long “error chain” between what the operator sees and what the close-permissive logic actually uses.

The WTM32 from ODES integrates this into a single device:

Synchroscope + synchro-check relay + phase-angle compensation + galvanic isolation in one unit.

The indication the operator sees is generated by the same sampling and algorithm that feed the internal close-permissive logic. Internal isolation and phase correction replace external angle shifters and isolation transformers. Panels become simpler, more reliable, and more economical over the full lifecycle.

More information on WTM32 and related synchronizing solutions is available at www.odes-electric.com.

1. One Measurement Core, One Decision Core – “What You See Is What the Logic Uses”

In traditional schemes, “what you see” and “what the logic sees” are often different:

The synchroscope measures one set of VT signals.
The synchro-check relay may be wired differently, or use a different scaling and algorithm.
A separate angle transducer may shift phase for one of them.

This creates classic problems:

The operator sees acceptable conditions, but the check relay blocks closing.
Or the operator sees marginal conditions, but the relay output suggests close-permissive.

WTM32 removes this inconsistency by design:

Voltage, frequency and phase-angle indications come from a single measurement core.
The same core feeds the synchro-check decision logic.
Sampling, filtering and algorithms are identical for display and for the close-permissive criteria.

Engineering impact:

No more “we are looking at A but deciding on B.”
Phase-angle windows are no longer squeezed by propagation delay between meter and relay.
Synchronizing becomes a short, closed loop from measurement, to decision, to close-permissive contact.

2. Eliminating External Angle Shifters: Built-In Phase-Angle Compensation

Conventional manual synchronizing schemes often use a phase-angle transducer (“angle shifter”) to correct sampling reference:

Aligning the displayed angle with the operator’s convention
Adapting to unusual VT wiring or generator connection arrangements

Each external angle device adds:

An extra core and burden
Additional terminal levels
A new potential point of miswiring or failure

WTM32 incorporates internal phase-angle compensation and self-angle strategies, allowing:

Configuration of phase-angle offsets in software rather than hardware
Adaptation to different VT and generator configurations without extra devices

Engineering benefits:

No separate angle transducer to specify, install and maintain
Fewer cores and fewer analogue links in the synchronizing chain
Easier configuration changes when projects or standards change

In short, phase-angle correction becomes a parameter, not a separate box.

3. Eliminating External Isolation Transformers: Internal Galvanic Isolation

In many designs, isolation transformers are added between:

Measurement paths and synchro-check relay inputs
Different grounding systems or VT groups

Reasons typically cited:

Galvanic isolation between measurement and decision channels
Separation of different reference points or shield systems

WTM32 implements the required isolation inside the device:

Measurement and decision sections are galvanically isolated within the hardware architecture.
The need for separate “measurement isolation VT” and “logic isolation VT” is removed in most common schemes.

Results:

Fewer iron cores and fewer panel-mounted transformers
Fewer terminal strips and fewer wiring hops
Lower probability of wiring errors, poor terminations or loose connections along the path

With WTM32, the synchronizing chain is effectively:

VT → WTM32 → synchro-check output contact → breaker close circuit

rather than VT → meter → angle transducer → isolation VT → check relay → close circuit.

4. Engineering Advantages: A Shorter “See–Decide–Close” Loop

Replacing four functions with one device is not just about saving space. It changes how the engineering loop looks.

4.1 One Device, Two Roles: Indication + Synchro-Check

WTM32 acts both as:

Synchroscope – giving the operator real-time voltage, frequency and phase-angle difference
Synchro-check relay – producing a close-permissive contact based on configurable criteria

The operator’s visual judgement and the relay’s binary decision are aligned by design.

4.2 One Device, Multiple Substitutions

In typical manual synchronizing schemes, WTM32 can replace:

Synchroscope
Synchro-check relay
Phase-angle transducer
Measurement / logic isolation transformers (in many cases)

Device count drops; so do:

Failure points
Wiring time
Drawing complexity

4.3 Simpler Delivery and Documentation

With WTM32, engineering deliverables become simpler:

Shorter wiring diagrams – fewer symbols and cross-references
Shorter terminal lists – fewer field terminals to number and check
Faster FAT/SAT – fewer devices to parameterise and verify

Over the lifecycle, spare-part management is easier:

One device family covers multiple synchronizing roles
Stock pressure and part multiplicity are reduced

4.4 Multi-Standard Friendly

For projects with multiple voltage and frequency standards (e.g., 50 Hz and 60 Hz regions, different VT secondaries), WTM32 offers:

Parameter configuration at one point
Avoids “one parameter set for the meter, another for the relay” mismatches
Supports rapid adaptation across different VT and frequency standards with a unified device

5. Implementation Guidelines for Manual Synchronizing with WTM32

To use WTM32 effectively as an all-in-one manual synchronizing element, consider the following steps.

5.1 Define Sampling and VT Interfaces

Decide whether each side is wired phase-to-neutral or line-to-line.
Match WTM32 inputs to actual VT secondaries (e.g., 57.7 V LN or 100 V LL).
Configure nominal voltage parameters accordingly.

5.2 Configure Synchronizing Criteria

Set limits for:
Ensure these limits are consistent with plant synchronizing practice and grid codes.

5.3 Wire Synchro-Check Contact into Close Circuit

Use WTM32’s synchro-check output contact as a series element in the breaker close circuit:
Confirm that when synchro-check is not satisfied, the close circuit is blocked regardless of operator action.

5.4 Commissioning and Test

Perform a structured synchronizing test:
Document settings and test results as part of FAT/SAT for future reference.

Conclusion: A Cleaner, More Deterministic Manual Synchronizing Architecture

Manual synchronizing does not have to involve multiple devices and long error chains.

The ODES WTM32 synchronizing meter integrates:

Synchroscope indication
Synchro-check close-permissive logic
Phase-angle compensation
Internal galvanic isolation

into a single DIN-panel device, reducing wiring, components and failure points while making the “see–decide–close” loop shorter and more deterministic.

For panel builders, system integrators and plant owners, this means:

Cleaner cabinet layouts
Higher reliability
Easier parameter management
Better lifecycle economics for manual synchronizing systems

If you are designing or retrofitting manual synchronizing panels and want to reduce devices, wiring and error sources, ODES can help you consult on WTM32-based architectures, request integrated wiring and setting templates, and learn how to replace synchroscope + synchro-check relay + angle transducer + isolation transformer with a single engineered device.