Decide which purchasing question the number answers
A quotation that says “low current” leaves two separate decisions unresolved: whether the motor delivers the required operation under load, and whether it supports the intended duration of use. A low unloaded reading does not answer either question. Start your comparison sheet with the application requirement, then put each supplier's evidence against it.
For a replacement order, identify the exact motor version and vehicle application already required by the parts specification. For a new assembly, the engineering requirement must define the relevant load and operation. Current comparison belongs after that identification step. It cannot independently establish vehicle compatibility, connector assignment or equivalent wiping performance.
Use the Wiper Motors product family to locate the proposed reference. A public product listing identifies an inquiry candidate; an application-specific report supplies the operating evidence. Keep the quoted reference and report revision together so an apparently similar version does not acquire another motor's results.
Sort the evidence into three operating states
No-load current describes the motor under an identified unloaded condition. It can be useful when comparing like-for-like motor records, but it does not include an unspecified installed mechanism. The word unloaded must be defined: a motor with its own gearing and a motor driving an external linkage are different comparison objects.
Starting current describes an event. Its value has meaning only with the reported measurement definition and observation interval. A peak captured at startup should remain labeled as a peak; placing it beside a running average in one unlabeled column creates a comparison the reports do not support.
Loaded running current describes operation against a specified load, with a defined speed or control setting. This is the relevant row when the buying question concerns a particular working condition. The report still needs to establish what operation was achieved under that load. Current by itself is an input observation, not a complete description of wiping output.
Build a comparison sheet that reveals mismatches
Give each offer a separate column and copy the original units and labels before normalizing anything. Mark missing fields as “not supplied.” The following worksheet is an editorial procurement tool, not a universal test standard. Its purpose is to show whether the two current figures answer the same question.
| Field to record | Why it changes the decision | Action when different or missing |
|---|---|---|
| Reference and revision | Defines the offered motor | Resolve version coverage first |
| State and achieved operation | Separates startup, unloaded and working results | Place values in separate rows |
| Measurement boundary | Defines what electrical load was included | Do not rank unlike boundaries |
| Supply and control setting | Defines the electrical operating condition | Request a common-condition result |
| Mechanical configuration and load | Defines the work represented | Resolve assembly differences |
| Statistic and observation interval | Defines what the displayed number means | Keep peak, mean and RMS separate |
| Cycle and thermal conditions | Defines the supported duration of operation | Keep duty approval unresolved |
This sheet separates a documentation gap from a failed requirement. An absent voltage field means the comparison is incomplete; it does not prove the motor failed. A recorded result outside an agreed acceptance limit is a different finding and should retain the report's conclusion. Avoid replacing either finding with a broad “good” or “bad” supplier label.
Match the electrical and mechanical boundaries
A current measured at a motor input and one measured at an assembly supply can include different components. The sheet should say where the measurement was taken and what was connected within that boundary. Without that definition, a difference in readings may reflect a difference in included equipment rather than the motor being compared.
Likewise, record the supply condition actually used in the observation and the speed or control mode. A nominal system label is not a substitute for the reported condition. If the offers were evaluated at different conditions, retain both records but do not present their numerical difference as an efficiency advantage.
For the mechanical side, distinguish a motor alone, a motor with linkage and a defined complete wiper assembly. Where the report involves blades and glass, its specified conditions belong in the comparison. A bare-motor result and an assembly result can both be useful; they address different boundaries and should occupy different rows.
The practical outcome is straightforward: matching fields permit review against a common requirement; mismatching fields call for a common-condition result or a documented explanation of applicability. A buyer should not attempt to correct one current figure with an invented multiplier for the missing load.
Read the statistic before calculating a difference
“Maximum current” can identify the largest captured reading, a permitted running limit or another defined quantity. Preserve the original definition. Mean, RMS and peak values should each have their own label and time window. They summarize an observation differently, so the report must identify which quantity is being compared.
Consider an explicitly hypothetical pair of offer summaries: A reports a 5 A startup peak, while B reports a 2 A loaded running mean. B is not demonstrated to draw less current under the same operation. The decisive issue is the different state and statistic; subtracting the numbers would add no useful comparison. Move them to separate rows and request the missing corresponding observations.
Instrument or acquisition details become relevant when an apparent difference depends on capturing a brief event. A displayed reading and a recorded transient may cover different intervals. For procurement review, keep the issuing report's method and uncertainty information where supplied; an unexplained sales number is not enough to resolve such a comparison.
Evaluate duty with the whole cycle
Duty percentage is a compact description of timing, but it omits the length of each interval. In a hypothetical worksheet, 30 seconds running followed by 90 seconds resting gives an on-time fraction of 30/(30+90), or 25%. A pattern of 60 seconds running followed by 180 seconds resting also gives 25%, while doubling the uninterrupted run interval.
Those schedules are examples for reading a report, not allowed cycles for a product. The shared percentage does not establish the same thermal behavior. A usable duty statement retains the run and rest intervals, repetitions, load, environment and initial state, along with the applicable acceptance conclusion. The percentage can remain as a summary once those fields are present.
Maxon's motor-data explanation describes dependence on temperature, installation and control conditions. Its EC-motor operating-range discussion explains the role of heat production and dissipation. These provide context for retaining conditions, rather than temperature limits or ratings for a MAKEXCAR motor.
Continuous operation needs its own supported operating envelope. Evidence for a brief peak or one completed cycle does not establish indefinite operation at that condition. When the requirement is continuous use and the offer provides only intermittent evidence, leave the continuous-use decision open until applicable documentation resolves it.
Apply the worksheet to a purchase review
Suppose two offers identify the same requested application, but one summary includes a motor-only no-load reading and the other includes a linkage-loaded reading. The useful next step is to request a matching loaded observation for the first offer, including the configuration and achieved operation. Asking for a generically “lower current” motor would move away from the actual evidence gap.
Now suppose both provide loaded results, but the proposed operating pattern differs from the documented cycle. The running-current comparison may be usable within its stated conditions while the duty decision remains unresolved. Record those as separate outcomes so a complete electrical row does not silently close an incomplete duration requirement.
Finally, if a new report shows a different current from an earlier one, compare versions and conditions before assigning a cause. A changed reading supports further investigation; it does not alone identify a faulty motor, an overloaded linkage or a control problem. Record the difference and the issuing party's explanation rather than adding a diagnosis to the order.
Send a focused RFQ and retain the decision
The following text can be adapted to the order. Replace bracketed fields with the requirement you actually have; leave unresolved application inputs visible to the engineering reviewer. It requests evidence rather than prescribing a test or inventing limits.
“We are reviewing [motor reference and revision] for [vehicle/application and required operating mode], quantity [quantity]. Please identify the report covering this offered version. For [specified working condition], provide the current definition, measurement boundary, supply/control conditions, mechanical configuration and achieved operation. State the supported run/rest pattern or continuous envelope, the associated thermal conditions and the acceptance basis. Identify any differences between our requirement and the reported configuration.”
Send the completed request through the MAKEXCAR sourcing contact. Keep the response, source report and quotation revision together. The comparison sheet should finish with a reasoned outcome: comparable within stated conditions, awaiting a particular missing field, or outside a documented requirement. That record tells the next reviewer exactly what was decided and what still needs evidence.
