1、MIL-T-15108C(NAVY)20 November 1975SUPERSEDINGMIL-T-15108B22 August 1955(See 6.4)MILITARY SPECIFICATIONTRANSFORMERS, POWER, STEP-DOWN, SINGLE-PHASE,60-HERTZ, 1-KILOVOLTAMPERE APPROXIMATEMINIMUM RATING, DRY TYPE, NAVAL SHIPBOARDThis specification is approved for use by all interested Commands of the D
2、epartment ofthe Navy and the Marine Corps and is available for use by all other Departments and Agenciesof the Department of Defense.1. SCOPE1.1 This specification covers dry type, 60-hertz (Hz), single-phase, electric trans-formers of standard mounting dimensions for shipboard use.2. APPLICABLE DOC
3、UMENTS2.1 The following documents, of the issue in effect on date of invitation for bids orrequest for proposal, form a part of this specification to the extent specified herein.SPECIFICATIONSFEDERALJ-W-1177 - Wire, Magnet, Electrical.MILITARYMIL-S-901-Shock Tests, H.I. (High-Impact); Shipboard Mach
4、inery,Equipment and Systems, Requirements for.MIL-E-917 - Electric Power Equipment, Basic Requirements (NavalShipboard Use).MIL-E-2036 - Enclosures For Electric and Electronic Equipment, NavalShipboard.MIL-P-15024 - Plates, Tags and Bands For Identification of Equipment.MIL-P-15024/5 - Plates Identi
5、fication.MIL-E-16366 - Electrical Clamps, Lug Terminals and Conductor Splices-Pressure Grip.MIL-W-16878/7 - Wire, Electrical, Type F, 200C, 600 Volts, (Insulated,High Temperature).MIL-E-17555 - Electronic and Electrical Equipment Accessories, and RepairParts; Packaging and Packing of.STANDARDSMILITA
6、RYMIL-STD-108 - Definitions of and Basic Requirements for Enclosures forElectric and Electronic Equipment.MIL-STD-195 - Marking of Connections for Electric Assemblies.(Copies of specifications, standards, drawings and publications required by suppliersin connection with specific procurement function
7、s should be obtained from the procuringactivity or as directed by the contracting officer.)3. REQUIREMENTSThe transformers furnished under this specification shall beproducts which are qualified for listing on the applicable qualified products list at timeset for opening of bids (see 4.3 and 6.3) .3
8、.2 Definitions. The definitions specified in 3.2.1 through 3.2.11 shall apply to thevarious technical terms specified herein.3.2.1 Transformer. A transformer is an electric device without continuously movingparts which by electromagnetic induction transfers electric energy from one or more circuitst
9、o one or more other circuits at the same frequency usually with changed values of voltageand current.FSC 6120Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-T-15108C(NAVY)3.2.2 Dry type transformer. A dry type transformer is a transformer cooled
10、by thenatural circulation of air.3.2.3 Primary winding. Primary winding is the winding on the input side.3.2.4 Secondary winding. Secondary winding is the winding on the output side.3.2.5 Tap in a transformer. A tap in a transfer-r is a connection brought out of awinding at some point between its ex
11、tremities, usually to permit changing the voltage ratio.3.2.6 Rated kilovoltampere kVA of a transformer. Rated kVA of a transformer is theoutput which can be delivered for the time specified at approximately rated secondary voltageand rated frequency without exceeding the specified temperature limit
12、ations.3.2.7 Ratio of a transformer. Ratio of a transformer is the turn ratio of the trans-former.3.2.8 Regulation of a transformer. Regulation of a transformer is the change insecondary voltage, expressed in percent of rated secondary voltage, which occurs when ratedkVA output at a specified power
13、factor is reduced from rated value to zero, with the primaryimpressed terminal voltage maintained constant. 3.2.9 Impedance voltage of a transformer. Impedance voltage of a transformer is thevoltage required to circulate rated current through a winding of the transformer when anotherwinding is short
14、-circuited, with the respective windings connected for rated voltage operationand is expressed in percent of the rated voltage of the winding in which the voltage ismeasured.3.2.10 Exciting current of a transformer.current which flows in any winding used to excite the transformer when all other wind
15、ings areExciting current of a transformer is theopen-circuited, and is expressed in percent of the rated current of the winding in which itis measured.3.2.11 Lead polarity of a transformer. Lead polarity of a transformer is a designationof the relative instantaneous directions of currents in its lea
16、ds. Primary and secondaryleads are said to have the same polarity when at a given instant the current enters theprimary lead in question and leaves the secondary lead in question in the same direction asthough the two leads formed a continuous circuit. The lead polarity of a single-phasedistribution
17、 or power transformer may be either additive or subtractive. If one pair ofadjacent leads from the windings in question is connected together and voltage applied toone of the windings:(a) Lead polarity is additive if the voltage across the other two leadsof the windings in question is greater than t
18、hat of the highervoltage winding alone.(b) Lead polarity is subtractive if the voltage across the other two leadsof the windings in question is less than that of the higher voltagewinding alone.# 3.3 General requirements. Transformers shall comply with the requirement of MIL-E-917and the requirement
19、s of this specification, except as otherwise specified in the contractor order. If any requirement specified herein conflicts with the requirements of MIL-E-917,the requirements of this specification shall govern.# 3.4 Insulation system. The insulation system shall be class 130 as specified inMIL-E-
20、917 or higher. The whole core and coil of each transformer shall have varnish appliedby the dipping process or vacuum-pressure process specified in MIL-E-917.# 3.5 Painting Painting shall comply with the requirements of MIL-E-917, except thatonly one coat of gray enamel need be applied. Marks or scr
21、atches made due to handling dur-ing fabrication and testing shall be repainted by either complete repainting of equipmentor by touchup method. Parts to be painted shall consist of those not having a corrosion-resisting treatment or not fabricated of corrosion-resisting materials of the types speci-f
22、ied in MIL-E-917 and shall include exterior and interior surfaces of the enclosure.# 3.6 Enclosure. Unless otherwise specified in the contract or order, transformers shallbe driproof (45 degree), in accordance with class I of MIL-E-2036 for electric equipment andwith MIL-STD-108. Enclosure shall pro
23、vide for the entrance of the ships cables. Readyaccessibility shall be provided with clearance in the vertical direction for installationand maintenance or electrical connections (see table III). Sufficient space shall be provided2Provided by IHSNot for ResaleNo reproduction or networking permitted
24、without license from IHS-,-,-MIL-T-15108C(NAVY)in the terminal compartment for making connections of single-phase transformers in closeddelta banks. The terminal compartment shall be so constructed that it is possible to dis-connect readily a transformer connected in a three-phase bank without distu
25、rbing the cableto the remaining transformers or other unit comprising the bank.# 3.7 Ambient temperature.temperature of 50C. The rating of transformers shall be based upon an ambient3.8 Rating.# 3.8.1 Voltage. Transformers shall be designed for the following voltages, as specified(see 6.2.1):120 - 1
26、20 no-load - Group 1.450 - 230 no-load - Group 2.450 - 120 no-load - Group 3.Special voltage.3.8.2 Phase. Transformers shall be designed for single-phase operation.3.8.3 KVA capacity Transformers shall be designed to have the following kVA capaci-ties as specified see 6.2.1):1.0 25.03.0 37.55.0 50.0
27、7.5 75.010.0 100.015.03.9 Duty. Unless otherwise specified (see 6.2.1), transformers shall be designed forcontinuous duty .# 3.10 Temperature limits. Transformers shall not exceed the values of maximum permissabletemperature rises specified table I.Table I - Maximum permissible temperaturerises at 1
28、00 percent load.Name of part Insulation systemclass 130Primary windingSecondary windingCoreby resistance method of MIL-E-917.by thermometer method of MIL-E-917.# 3.11 Characteristics. Characteristics of the transformers shall be as specified intable II.Table II - Transformer characteristics.3Provide
29、d by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-T-15108C(NAVY)Table II - Transformer characteristics (con.).Transformer to be submitted from each division for qualification (see 4.3.1) .Mounting feet and braces included in the “E” and “F“ dimensions spe
30、cified on figures 1and 2.Regulation impedance and total losses are to be based on a reference copper temperatureof 75C.Values for inrush current are applicable to transformers with 450-volt primary. Themaximum peak inrush current for transformers with other primary voltage ratings shallbe the same p
31、ercentage of the primary load current.3.12 Ratio. Transformers turn ratio shall not vary more than plus or minus 1.0percent from ratio of rated voltages indicated on the identification plates.3.13 Polarity. Transformers shall be of additive polarity.# 3.14 Shockproofness. Transformers shall be desig
32、ned to withstand high-impact shockwithout mechanical damage or failure of parts as specified in MIL-S-901 for grade A, class I,type A (see 4.6.10).# 3.15 Short circuit. Transformers shall be designed to withstand the short circuit testspecified in 4.6.13.# 3.16 Weight. Transformers complete with cas
33、e and including wiring and mounting pro-vision shall not exceed the weights shown in table II.# 3.17 Volume. Transformers volume shall not exceed the volume in cubic inches shownin table II. Maximum dimension in each direction shall be used in determining the volume.# 3.18 Dielectric strength. Trans
34、formers shall be designed and constructed so thatthe insulation system for each separate winding will withstand a root means square (rms)dielectric test voltage of 4000 alternating current (a.c.) volts, sinusoidal waveform,60 Hz, applied for 1 minute between the winding and all other windings connec
35、ted togetherand grounded to the core(s) and frame.# 3.19 Mounting. Mounting dimensions of transformers shall be as specified on figures1 and 2. Holes provided for mounting and bracing shall not be slotted. Transformers withkVA rating 1 through 25 kVA shall be bulkhead mounted. Transformers with kVA
36、rating 37.5kVA and larger shall be deck mounted. Transformers, when in place onboard ship, are mountedin banks with a minimum distance of 2 inches between units. Under this condition, thetemperature rises (see 3.10) shall not be exceeded. Braces will be provided by the ship-builder.# 3.20 Winding re
37、sistance. Measured values (see 4.6.1) of winding resistance correctedfor temperature difference shall be compared to the design value of applicable windingresistance given on the transformer drawing, and deviations therefrom shall be computed inpercent of design value. The algebraic average of all s
38、uch deviations (for windings) oftransformers on each contract or order shall fall within the limits of minus 5 to plus 0 per-cent, inclusive. Each winding individually shall fall within the range limits of minus 10plus 5 percent, inclusive.4Provided by IHSNot for ResaleNo reproduction or networking
39、permitted without license from IHS-,-,-MIL-T-15108C(NAVY)# 3.21 Spot welding or tack weldinq. Spot welding or tack welding shall not be usedfor structural parts subject stress or shock.# 3.22 Liftinq means. Transformers of 10 kVA capacity and over shall be provided withmeans for lifting and handling
40、 by use of eye-bolts.3.23 Windings.3.23.1 Transformers shall have separate primary and secondary windings insulated fromeach other and from metal parts.#3.23.2 Windings shall be supported so that mechanical stresses caused by short circuits(see 4.6.13) and shock will not be reflected in the weakenin
41、g of the insulation, permanentdeformation of the windings, or other mechanical or electrical injury.3.23.3 Taps shall not be permitted.3.23.4 Magnet wire for transformers shall be in accordance with J-W-1177.3.24 Core. Laminations shall be properly insulated from each other. In the assemblyof the co
42、re, care shall be taken to remove all burrs or projecting laminations which mightresult in injury to the coils. Laminations shall be clamped together in such a manner as toinsure a tight core. During the process of manufacture, the assembled core shall be givena varnish dip. Laminations shall be ann
43、ealed for stress relieving after punching or forming.3.25 Identification plates.# 3.25.1 General. Identification plates shall be as shown on figure 3 and in accordancewith MIL-P-15024 and MIL-P-15024/5. Plates shall be installed on and furnished as a part ofeach transformer and shall be located so t
44、hat they can be easily read at all times withoutdanger to personnel. Unless otherwise specified in the contract or order, the identificationplates shall be located on the front of the enclosure.# 3.25.2 Data on identification plates. The minimum data to be marked on the identificationplates for tran
45、sformers shall be as shown on figure 3.3.25.3 Connection diagram plate. Connection diagram, schematically showing the actualconnections for three-phase operation, instructions for connecting in open delta and thepercent kVA capacity for open delta to be provided as shown on figure 3.3.26 Connections
46、 and terminals.# 3.26.1 Ships cable supports shall not be furnished. However, for sizes larger than50 kVA, a removable angle iron ships cable support bracket extending horizontally acrossthe cable compartment, shall be furnished. This bracket shall act as a base on which theinstalling activity may m
47、ount, if desired, for the particular installation, a ships cablesupport. The top of the bracket shall be 2 inches wide and 2 inches above the core andcoils, whichever is highest.# 3.26.2 Terminal boards shall not be used. Transformer leads shall be secured by theuse of an insulated support and arran
48、ged in such a manner that the connections to shipscables may be made by the use of solderless connectors conforming to MIL-E-16366. Solderlessconnectors need not be furnished with the transformer.3.27 Cable compartments.3.27.1 Location. Location of cable compartments with respect to transformer kVA
49、ratingshall be as follows:(a) 1 through 10 kVA - cable compartment at bottom.(b) 15 kVA and larger - cable compartment at top.3.27.2 The minimum thickness of cable compartment removable side plates with respectto transformer kVA size shall be as follows:(a) 1 through 25 kVA - U.S. gage 16 (0.0598 inch).(b) 37-1/2 kVA and larger - U.S. gage 15 (0.0747 inch).5Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-#MIL-T-15108C(NAVY)3.
