Dry-type transformer temperature monitoring needs an agreed interface schedule before order and design release. Identify the sensors, controller power supply, alarm and trip outputs, cooling controls, and any building-management connection. A quotation that says “temperature controller included” leaves these boundaries unresolved. Ask the transformer supplier, electrical designer and controls contractor to approve the same schedule, with drawing references and an owner for each open point.
This guide is for EPC and procurement teams buying medium-voltage dry-type transformers for IEC-specified industrial projects. It concerns documentation before order and design release. It does not provide wiring instructions, protection settings or commissioning procedures.
Dry-type transformer temperature monitoring supply scope
List the supplied components and their responsibilities separately. Record whether the offer includes embedded sensors, connecting leads, a terminal box, a controller, its enclosure, cooling equipment and any communication option. Identify items supplied by the transformer manufacturer, panel builder or site contractor.
Do not treat a controller display as proof that a complete protection or remote-monitoring system is included. Ask for the proposed model and option code, a current manual and the associated control drawing. Any substitution should return for interface review before approval.
The IEC catalogue for IEC 60076-11:2018 defines the scope of that dry-type transformer standard. A general reference to the standard does not identify the controller options or the project's alarm and trip logic. State both the transformer standard and the separate interface requirements.
Match the sensors to the proposed controller
Request the sensor specification rather than accepting “temperature sensor” as a complete description. The schedule should identify the sensing technology, number of channels, location of each sensor and its connection arrangement. A Pt100 resistance-temperature input and a thermocouple input are different specifications; compatibility needs confirmation for the proposed devices.
Ask which channels measure windings and which, if any, measure the core or surrounding air. Keep those measurement locations explicit in the drawings and remote point list. A room-air measurement should not be labelled as winding temperature.
Record who supplies the sensor cable between the transformer and controller, where that responsibility ends, and which installation instructions apply. Cable routing and termination remain tasks for the responsible electrical designer and qualified installation team.
Describe alarm, trip and fault behaviour explicitly
Specify what each output means and where it goes. Separate a high-temperature alarm, a trip request, a sensor or controller fault, and a cooling command. Do not combine them under a single “alarm contact” description.
For each contact, request its identification, electrical rating for the intended duty, and state in the conditions the project requires: healthy operation, alarm, controller power loss and sensor failure. The controls designer should confirm the receiving circuit and whether additional interface equipment is needed.
Use an approved cause-and-effect schedule to connect each condition with the required response. Record who approves thresholds, delays, reset behaviour and any latching function. Copying a controller's default settings into a purchase order does not establish that those settings suit the transformer or the plant.
Separate controller power from cooling responsibilities
Confirm the controller supply and the cooling circuit as separate interfaces. State the available supply voltage, AC or DC, and the relevant site power arrangement. Identify who provides the supply, its protection and the associated drawings.
When fans are required, ask whether the offer includes the fans, power circuit, switching equipment, control command and any status feedback. A signal requesting fan operation does not establish that the project receives proof of actual operation. Document the required feedback separately.
Transformer cooling controls and building ventilation controls also have different owners. For room-level heat information, use the dry-type transformer room ventilation guide; retain the equipment signal schedule here.
Specify the BMS connection by usable information
Define the information the building management system needs, then confirm the offered interface. List required temperature values, alarm states, equipment faults and cooling status. Mark each item as included, optional, unavailable or awaiting confirmation.
If a digital protocol is proposed, request its exact implementation, communication settings and device point or register map. The Modbus Organization's introduction explains the distinction between protocol commands, physical networking and device mapping. “RS-485” or “Modbus” alone is therefore insufficient for a complete integration schedule.
For each value, document its label, units, scaling and interpretation of invalid or unavailable data. Name the party responsible for translating controller information into the site's BMS display. The project engineer must separately approve any protection function; a successful remote display is not evidence that the trip chain has been accepted.
Use one approval schedule before design release
Keep each interface tied to a document revision and an approving party. A practical schedule can use the following headings:
- Function and equipment tag
- Proposed device or option and supporting manual
- Sensor, supply, contact or communication requirement
- Transformer-side and site-side drawing references
- Supplier, installer, integrator and approval responsibilities
- Open issue, agreed response and approval status
Request an agreed verification plan describing the functions to be demonstrated, required records and responsible parties. Leave test methods to the approved procedures. Preserve the final settings record, point list, drawings and issue closures in the handover file.
A minimum monitoring interface register
| Interface | Required record | Decision to close |
|---|---|---|
| Sensors | Type, channels, locations and connection drawing | Does the selected controller accept the supplied sensors? |
| Controller power | Supply requirement and site circuit reference | Who supplies and approves the auxiliary power interface? |
| Alarm, trip and fault | Contact ratings, states and cause-and-effect schedule | Who approves settings, receiving circuits and failure behaviour? |
| Fan control | Command, power and feedback scope | Is actual operation feedback required and included? |
| BMS data | Exact protocol option, point map, units and scaling | Who verifies that the required points reach the BMS? |
Include this register with the transformer RFQ inputs and identify provisional entries before requesting a technical proposal.
For the wider evidence request, review the project technical documents and identify the records required before approval.
Frequently asked questions
Does every dry-type transformer include a temperature controller?
Do not assume it does. Check the proposed supply schedule and identify sensors, controller and options individually before comparing offers.
Can a replacement controller be selected by its display size?
No. Sensor inputs, power supply, output behaviour, communication options and the approved control logic all need review. Mechanical fit is only one part of compatibility.
Can procurement choose the alarm and trip temperatures?
Procurement should obtain and track approved settings, rather than invent them. The responsible technical parties must establish the values for the actual transformer design and application.
Is a communication port enough for BMS integration?
No. Confirm the protocol, available points, mapping and integration responsibilities. Check the exact offered option rather than assuming every controller variant has the same functions.
What should remain open if the controls contractor is not appointed?
Identify the unresolved receiving interfaces and nominate the party who will close them. Avoid approving a final interface schedule while essential supply or signal requirements remain unknown.
Prepare the monitoring requirements for HEAKOR
Start with the HEAKOR dry-type transformer enquiry page. Include the destination, phase, rated power, voltages, frequency, installation environment and required monitoring functions. Attach the available control philosophy and mark undecided interfaces clearly.
Submit Your Project Specification for review of the proposed equipment and open requirements. Sensor arrangements, controller options, communications, documents and supply responsibilities must be confirmed in writing for the offered configuration.