ปรับปรุงครั้งล่าสุด: October 8, 2026
คำตอบด่วน: Verify the received supply’s complete model and front-facing output markings, then link each identified contact to the controlled harness and equipment drawing. On the photographed WEHO NDR-75-24, the four upper contacts read −V, −V, +V, +V; repeated contacts do not establish independent outputs.
A replacement supply can carry the correct voltage marking while the equipment drawing still points to the wrong output contact. Procurement teams therefore need a clear record linking the received model, the physical terminal view and the destination circuit before assembly proceeds. Power supply polarity verification starts with that evidence. It helps a buyer distinguish an identified positive or negative terminal from an assumption based on wire color, cabinet position or a photograph of a similar product.
The WEHO NDR-75-24 provides a concrete example. Its photographed front has four upper DC contacts marked −V, −V, +V and +V, plus a separate three-contact lower input group. This article explains how an OEM can document that distinction, organize supplier questions and hand over a traceable terminal record. The equipment illustrations represent disconnected assembly contexts; their presence does not establish an approved load, operating circuit or completed electrical test.
ประเด็นสำคัญ
- Record the complete NDR-75-24 model and the received unit’s actual label before transferring a terminal reference.
- Define the viewing direction: the upright front has four upper DC contacts marked −V, −V, +V, +V and a separate lower input group.
- Bind contact identification to controlled harness and equipment documents; a wire color or scene photograph does not approve a circuit.
- Keep the documented 32mm width, 125.2mm height and 102mm depth distinct when reviewing the enclosure.
Identify the received unit before interpreting a terminal
Start the review with the complete model on the received product. Record NDR-75-24 rather than only NDR, 75W or a purchasing shorthand. A family name cannot establish the voltage variant, the terminal arrangement or the revision supplied. Preserve an original overall photograph and a readable front view with the model and output marking in the same record. Link those photographs to the purchase order, supplier reference and equipment drawing revision.
The source specimen reads OUTPUT: 24V with a DC symbol and 3.2A. Its input marking reads 100–240VAC, 1.6A and 50/60Hz. These are observations of the photographed sample. They should not be silently replaced with a different input-current entry or broader frequency range from a family table. The official English product table supports the NDR-75-24 voltage and current identity, but the documentation accompanying the ordered revision remains the basis for an equipment approval.
An identity record also prevents accidental comparison with the wrong housing. The photographed NDR-75-24 has a narrow blue printed front, silver metal sides and honeycomb ventilation openings. The front contains a DC OK indicator opening and an adjustment control. A blue plastic enclosure, an added relay connector or a blank front belongs outside this specific source example. If a received unit differs, retain its actual photographs and ask the supplier to identify the difference before transferring an older terminal record.
State the viewing direction in the terminal record
A label such as “left output” is incomplete without a viewing direction. Use a front-facing photograph with the model upright and describe the contact group being reviewed. For this specimen, the four upper front contacts read −V, −V, +V, +V from left to right. The lower group reads protective-earth symbol, N and L. Keep the DC output identification separate from the lower input identification throughout the purchasing and drawing record.
The complete NDR-75 mechanical sheet defines the upper TB2 group as drawing pins 4 and 5 for DC OUTPUT −V and pins 6 and 7 for DC OUTPUT +V. The drawing reference and the visible markings should be recorded together. A terminal number taken from a side view, an inverted photograph or another series may not describe the same physical point. The photograph should make it possible for a second reviewer to reproduce the identification without guessing which face was used.
Repeated polarity labels are not evidence of separately regulated or isolated channels. The source describes a single-output supply. Record the two negative and two positive contact positions without inventing independent output-channel behavior. If the assembly plan proposes more than one destination branch, the branch arrangement needs its own approved drawing and circuit review. The existence of additional contacts does not settle the permissible loading or protection of those branches.
Separate terminal identity from the equipment circuit
A reliable handover links three records: the supply contact, the harness or terminal-block reference, and the destination electronics. Each record should identify its owner and revision. The supply photograph answers which physical point carries a polarity marking. The equipment drawing answers where the approved circuit intends that point to go. A harness record explains the intervening connector or wire identification. None of these records can replace the other two.
Consider an OEM parts-washing machine during controller assembly. The supply may already sit on its DIN rail while the controller interface and harness are still awaiting termination. That is a useful moment to capture a readable front view and settle the contact reference. The equipment context makes the documentation task concrete, but stainless equipment, a nearby circuit board or a nominal voltage match does not prove that the selected supply can operate the machine or tolerate its environment.
Avoid allowing a cabinet photograph to become an undocumented wiring instruction. A cable routed toward a terminal is not evidence of its destination, and a familiar wire color is not sufficient evidence of polarity. The equipment designer or qualified assembly team should control the connection drawing and the required checks. Procurement can support that work by delivering clear source evidence and resolving inconsistent documents before the electrical assembly stage.
Keep the enclosure and mounting revision in scope
Physical fit matters because it changes access to labels and contacts. The complete source drawing gives a 32mm width, 125.2mm height and 102mm depth. Those axes describe a narrow front and a deeper metal enclosure. Keep width, height and depth distinct in the mechanical review; rotating a dimensional tuple or measuring only the visible front can produce an incorrect clearance assumption. Use the controlled drawing with the proposed cabinet arrangement rather than estimating fit from an application photograph.
The original rear view shows the metal mounting bracket and spring-operated lower DIN latch. The official English source identifies TS-35/7.5 or TS-35/15 rail installation. A mechanical record should identify the selected rail and the actual product attachment, then leave final installation and access approval with the equipment team. Nearby wire ducts, door hinges and other components also affect service access. The product dimensions alone do not establish a complete cabinet layout or an approved separation distance.
Preserve the photographed casing details when comparing revisions. The documented left side of this specimen has its own screws, slots and circular feature; its opposite inspection face is a different view. The complete drawing and actual sample photographs should be examined together when a mechanical feature needs clarification. Do not treat a missing feature in one projection as permission to redraw the received product or substitute an unrelated housing in the purchasing record.
Prepare evidence that travels with the assembly
A terminal record is most useful when it survives a shift change, supplier discussion or replacement order. Give the record an identifier and include the complete model, source photographs, drawing revision, date, reviewer and open questions. Capture the product label and the relevant contact group at a readable resolution. Include enough surrounding geometry to distinguish the upper output group from the lower input group without relying on a cropped letter alone.
A pneumatic leak-test fixture illustrates a different equipment arrangement. The control bay may sit beside a clamped manifold and test tubing, with the supply positioned away from the fixture itself. The same documentary sequence still applies: identify the received unit, define the front view and bind the intended destination through the approved drawing. The scene does not establish a pressure rating, an electronics load or permission to connect the pictured contacts.
Store the evidence where both purchasing and engineering can retrieve it. A useful handover references original files rather than a screenshot pasted into an informal message. It also records what remains unresolved. If a model suffix, terminal marking or drawing version differs, describe the difference precisely and request confirmation. An unresolved item should stay visible until the responsible reviewer closes it; an attractive photograph or a supplier quotation does not close a technical discrepancy by itself.
Ask the supplier questions that can be answered
Send a compact evidence request when an inconsistency appears. Include the purchase reference, complete model, received-unit label, overall front view and the disputed drawing extract. Ask which document revision applies to that unit and request a confirmed terminal view for the ordered variant. Clear references help the supplier answer the actual question without guessing whether the issue concerns voltage, polarity, mechanical fit or a different production revision.
Separate documentation questions from system-design questions. Confirmation that two contacts are marked +V establishes their identification; it does not approve a customer harness or decide its protection. Confirmation of the nominal 24V output does not establish startup behavior, current demand or compatibility with a particular controller. Where the equipment review needs those facts, request the appropriate technical evidence and have the responsible team evaluate it against the actual application.
บทสรุป
For repeat purchases, keep the accepted record with the order specification and define how a changed label or enclosure will be handled. This gives receiving inspection a concrete comparison and reduces the chance that a substitution is treated as identical because it fits the same cabinet space. Power supply polarity verification then becomes a practical bridge between sourcing and engineering: exact contact evidence reaches the people responsible for the circuit before connection decisions are made.
Sources and product discussion
The example uses the official English NDR-75 product page, the complete WEHO NDR-75 specification and mechanical sheet, and original NDR-75-24 front, left, opposite-side and rear photographs from the WEHO enterprise source library. Literal sample labels and drawing references are kept distinct from broader family-table operating entries. Application scenes are illustrative disconnected assemblies, not commissioned installations or customer case studies.
For an OEM documentation request, provide WEHO with the complete model, order reference, terminal-view question and equipment drawing revision. This allows the product discussion to focus on the received variant and the evidence needed for the next engineering decision.
คำถามที่พบบ่อย
Which NDR-75-24 contacts identify the DC output in this example?
With the photographed front upright, the four upper contacts read −V, −V, +V and +V from left to right. The complete NDR-75 sheet assigns TB2 drawing pins 4 and 5 to DC OUTPUT −V and pins 6 and 7 to DC OUTPUT +V. Confirm the document revision against the received unit.
Do two positive and two negative contacts establish independent outputs?
No. The source describes a single-output supply. Repeated polarity markings identify contact positions; they do not establish separately regulated or isolated channels, or approve a proposed branch circuit.
Can wire color alone establish the correct connection?
Wire color alone is insufficient for the documentary handover. Link the identified supply contact to the controlled harness reference and approved equipment drawing. The responsible equipment team must control the actual connection and verification requirements.
Which dimensions belong to the source NDR-75 enclosure?
The complete source drawing gives 32mm width, 125.2mm height and 102mm depth. Keep the axes distinct and review the actual rear DIN attachment and cabinet arrangement; an application photograph does not approve installation clearances.
What should an OEM send WEHO when a label and drawing differ?
Provide the complete model, order reference, readable received-unit label, overall front view, disputed drawing extract and document revision. Request the applicable revision and confirmed terminal view for the ordered variant before transferring an earlier record to the assembly.
