{"id":199,"date":"2026-07-09T08:52:35","date_gmt":"2026-07-09T08:52:35","guid":{"rendered":"https:\/\/industrialelectricmotor.net\/?p=199"},"modified":"2026-07-09T08:52:35","modified_gmt":"2026-07-09T08:52:35","slug":"worm-gear-motor-for-barrier-gate-and-security-gate","status":"publish","type":"post","link":"https:\/\/industrialelectricmotor.net\/fi\/worm-gear-motor-for-barrier-gate-and-security-gate\/","title":{"rendered":"Worm Gear Motor for Barrier Gate and Security Gate"},"content":{"rendered":"
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Korea Ever-Power \u00b7 NMRV Series \u00b7 Barrier Gate and Security Gate Drive Guide<\/span><\/p>\n

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Worm Gear Motor for Barrier Gate and Security Gate:
\nSelf-Locking, Torque and Duty Cycle Selection Guide<\/span><\/h1>\n

Barrier gates, security boom gates, sliding security gates, and rising bollards all share the same fundamental drive requirement: a motor gearbox that can lift, rotate, or push a gate or barrier from rest to the fully open position quickly, hold it reliably at the open position, then return it to the closed position under precise control. The worm gear motor is the standard mechanism for these applications because the self-locking property of high-ratio worm gears prevents the gate from being forced open manually when the motor is not energised \u2014 providing intrinsic mechanical security without a separate electric brake. This guide covers worm gear motor selection for boom barriers, sliding security gates, rising bollards, and industrial swing gate applications.<\/p>\n

Self-Locking Security<\/span>
\n2\u20136 s Open Time<\/span>
\nS3 High Cycle Duty<\/span>
\nOutdoor IP55<\/span>
\nNMRV 030\u2013063<\/span><\/div>\n<\/div>\n<\/div>\n

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Self-lock<\/div>\n
Ratio > 30:1 holds closed<\/div>\n<\/div>\n
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2\u20136 s<\/div>\n
Barrier arm raise time<\/div>\n<\/div>\n
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S3 15%<\/div>\n
Typical barrier duty<\/div>\n<\/div>\n
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30:1\u201380:1<\/div>\n
Typical ratio range<\/div>\n<\/div>\n
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IP55<\/div>\n
Outdoor installation<\/div>\n<\/div>\n<\/div>\n

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\"NMRV<\/p>\n
Korea Ever-Power NMRV worm gearmotor for barrier gate and security gate drives \u2014 the self-locking property at ratios of 30:1 and above prevents the gate from being pushed open manually when the motor is de-energised, providing mechanical security without a separate electric brake. Compact NMRV 030 to 063 sizes fit within the barrier cabinet envelope with the Y2 or YS motor mounted directly on the gearbox input.<\/div>\n<\/div>\n

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Contents<\/div>\n
1. Gate and Barrier Drive Types<\/a>
\n2. Self-Locking Principle and Security<\/a>
\n3. Torque and Opening Time Calculation<\/a>
\n4. S3 Duty and High Cycle Applications<\/a>
\n5. Outdoor IP55 and Temperature Range<\/a>
\n6. NMRV for Barrier Gate Applications<\/a>
\n7. Barrier and Security Gate Applications<\/a>
\n8. Frequently Asked Questions<\/a><\/div>\n<\/div>\n

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1. Gate and Barrier Drive Types<\/h2>\n
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Boom Barrier (Raising Arm)<\/div>\n

The boom barrier rotates a counterbalanced arm from horizontal (closed) to vertical (open) through approximately 90 degrees. The counterbalance spring reduces the motor torque required to lift the arm \u2014 the spring does most of the lifting work, and the motor primarily controls the speed and acceleration. The worm gearmotor output shaft is connected to the arm pivot, and the arm rotates in 2 to 6 seconds depending on the application. Fast-acting barriers for high-traffic carparks: 1.5 to 2.5 s open time. Security barriers: 3 to 6 s open time with obstacle detection.<\/p>\n<\/div>\n

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Sliding Security Gate<\/div>\n

Industrial security gates slide horizontally along a rail or cantilever from one side of the gate opening. Gate widths from 2 m to 12 m with leaf weights from 50 to 2,000 kg. The worm gearmotor drives a rack-and-pinion or chain drive mechanism that moves the gate leaf along the rail. Opening time typically 10 to 30 seconds. Self-locking prevents the gate from being pushed open manually when the motor is off.<\/p>\n<\/div>\n

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Swing Gate<\/div>\n

Industrial swing gates (single or double leaf) rotate about a vertical hinge post through 90 to 120 degrees. The worm gearmotor is mounted at the hinge point and rotates the gate leaf about the hinge axis. Gate leaf weights from 50 to 500 kg. Opening time 10 to 30 seconds for industrial access gates. Self-locking holds the gate closed in wind gusts and prevents manual forcing when de-energised.<\/p>\n<\/div>\n

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Rising Bollard<\/div>\n

Security bollards rise from below ground level to above vehicle clearance height (typically 600 to 900 mm above grade) to block vehicle access. The worm gearmotor drives a vertical lifting mechanism through a 60:1 to 80:1 ratio providing high lift force from a small motor. Rising time 3 to 5 seconds. The very high self-locking torque at these ratios prevents the bollard from being pushed down by vehicle contact when the motor is off.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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2. Self-Locking Principle and Security Benefit<\/h2>\n

The self-locking property of a worm gear pair arises when the lead angle of the worm thread is less than the friction angle of the worm gear mesh. At gear ratios above approximately 30:1 for a single-start worm, the gear cannot be back-driven from the output shaft \u2014 any torque applied at the output shaft is converted entirely to heat in the worm mesh contact rather than rotating the worm shaft. This means the output shaft is mechanically locked without any external holding device when the motor is de-energised.<\/p>\n

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Self-Locking Torque at 40:1 Ratio<\/div>\n

Forward drive efficiency: 72%
\nBack-drive efficiency: negative (self-locking)
\nMotor rated torque: 2.0 N\u00b7m (0.37 kW, 4-pole)
\nOutput torque forward: 2.0 \u00d7 40 \u00d7 0.72 = 57.6 N\u00b7m
\nForce on boom arm at 300 mm radius: 192 N<\/p>\n

Back-drive resistance: theoretically infinite \u2014 arm cannot be pushed down manually against the locked worm mesh.<\/p>\n<\/div>\n

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Worm vs Helical Gearbox for Gates<\/div>\n

A helical gearbox (efficiency 95 to 97%) does NOT self-lock \u2014 the gate can be pushed open manually when the motor is off because the helical gear mesh can be back-driven. To use a helical gearbox for a security gate, a separate electric brake or a mechanical lock solenoid is required to hold the gate closed. The NMRV worm gearmotor provides self-locking as an inherent mechanical property at ratios above 30:1, eliminating the cost and complexity of a separate locking mechanism. For barrier gate and security gate applications requiring intrinsic mechanical security, the NMRV worm gearmotor is the correct choice over the higher-efficiency helical gearbox.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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3. Torque and Opening Time Calculation<\/h2>\n
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Boom Barrier Gearmotor Sizing \u2014 3m Counterbalanced Arm<\/div>\n
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Given:<\/div>\n
Arm length: L = 3.0 m
\nArm weight: W = 18 kg (aluminium boom)
\nCounterbalance spring: 80% of arm torque offset
\nRemaining torque at pivot: T-arm = 18 \u00d7 9.81 \u00d7 1.5 \u00d7 0.20 = 53 N\u00b7m
\nRequired open time: 3.0 s (90\u00b0 rotation)
\nOutput shaft angular velocity: \u03c9 = (\u03c0\/2) \u00f7 3.0 = 0.524 rad\/s = 5.0 rpm<\/div>\n<\/div>\n
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Motor and ratio selection:<\/div>\n
Required output speed: 5.0 rpm
\n4-pole motor at 1,450 rpm: ratio = 1,450 \u00f7 5.0 = 290:1
\nUse 2-stage: NMRV 40:1 \u00d7 chain 7.5:1 = 300:1 OR
\n2-pole motor at 2,850 rpm: single NMRV 60:1 = 47.5 rpm \u2192 5 rpm via 9.5:1 belt
\nSimpler: NMRV 063, 60:1, 2-pole 0.18 kW: output 47.5 rpm, use intermediate chain
\nSelect: NMRV 040, 40:1 + 6:1 chain = 240:1 from 4-pole 0.25 kW YS motor<\/strong><\/div>\n<\/div>\n<\/div>\n<\/div>\n

For boom barriers with factory-built counterbalance spring assemblies, the spring offset reduces the effective arm torque to 10 to 25% of the unbalanced torque, allowing the selection of small NMRV 030 or NMRV 040 gearmotors with motors as small as 0.06 to 0.18 kW for standard 3 to 4 m boom arms. Confirm the residual unbalanced torque with the barrier arm manufacturer before calculating the gearmotor specification.<\/p>\n<\/div>\n

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4. S3 Duty Rating and High-Cycle Barrier Applications<\/h2>\n
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Car Park Barrier \u2014 Very High Cycle<\/div>\n

Shopping centre and workplace carpark barriers may perform 500 to 2,000 operations per day. Each operation is 2 to 3 seconds open plus 2 to 3 seconds close. At 2,000 ops\/day: 4,000 s motor-on time per day from an 86,400 s day = 4.6% CDF. This is S3 5% duty. The NMRV worm gearmotor thermal rating at S3 5% allows a significantly smaller motor than S1 continuous for the same peak torque output.<\/p>\n<\/div>\n

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Security Barrier \u2014 Moderate Cycle \u2605<\/div>\n

Port and airport security barriers: 50 to 200 ops\/day. 4 to 6 second open and close. At 200 ops\/day \u00d7 10 s\/op: 2,000 s\/day = 2.3% CDF = S3 5%. However, security barriers may have high-force impact resistance requirement: specify gearbox for 3\u00d7 normal torque overload capacity for vehicle impact protection.<\/p>\n<\/div>\n

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Industrial Gate \u2014 Low Cycle<\/div>\n

Factory perimeter gates and loading dock security gates: 10 to 50 ops\/day. 15 to 30 second open and close for large sliding gates. Very low CDF (below 1%). NMRV gearmotor thermal rating is never challenged at this cycle rate. Motor selection driven by peak torque to move gate leaf, not thermal duty.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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5. Outdoor IP55 and Temperature Range for Gate Motors<\/h2>\n
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IP55 for Rain and Hosing<\/div>\n

Barrier gate and security gate gearmotors are almost always installed outdoors, exposed to rain, wind-driven water, and periodic hosing or pressure washing of the gate cabinet and surrounding area. IP55 (dust-tight, protection against water jets) is the minimum enclosure rating for outdoor gate motors. The Y2 and YS motors in the NMRV gearmotor combination are rated IP54 standard; specify IP55 upgrade for outdoor gate installations. The NMRV gearbox itself must also be sealed to IP55 with synthetic gear oil fill for outdoor service.<\/p>\n<\/div>\n

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Low-Temperature Starting<\/div>\n

Outdoor gate motors in cold climates may need to start against a frozen or ice-laden gate leaf at ambient temperatures below -15\u00b0C. Three concerns at low temperature: standard NMRV mineral oil thickens dramatically below -15\u00b0C, increasing the viscous drag on the worm mesh and requiring more starting torque; motor starting torque is slightly reduced at low temperature; and counterbalance springs become stiffer and may not offset arm weight as effectively as at rated temperature. Specify synthetic PAO gear oil in the NMRV for cold climate service, and verify that the motor locked-rotor torque at the minimum operating temperature is sufficient to overcome the increased viscous drag plus the unbalanced gate load.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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6. Korea Ever-Power NMRV for Barrier Gate Applications<\/h2>\n
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The Korea Ever-Power NMRV gearmotor is the compact right-angle worm gearmotor solution for boom barriers, security gates, sliding gates, and rising bollard drives requiring self-locking, high output torque, low output speed, and outdoor IP55 protection. NMRV 030 to 063 sizes with YS small-power or Y2 standard motors from 0.06 to 1.1 kW cover all boom barrier and medium-duty sliding gate applications. The complete NMRV gearmotor range is in the gearmotor product section<\/a>. For high-security bollard and heavy industrial gate specifications above 1.5 kW, contact Korea Ever-Power<\/a> for custom configuration.<\/p>\n<\/div>\n

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NMRV \u2014 Barrier Gate Data<\/div>\n\n\n\n\n\n\n\n\n\n\n
Sizes for gates<\/td>\nNMRV 030\u2013063<\/td>\n<\/tr>\n
Ratio range<\/td>\n30:1\u201380:1<\/td>\n<\/tr>\n
Self-locking<\/td>\nYes at 30:1 and above<\/td>\n<\/tr>\n
Motor options<\/td>\nYS 0.06\u20130.75 kW \/ Y2<\/td>\n<\/tr>\n
IP gearbox<\/td>\nIP55 (outdoor option)<\/td>\n<\/tr>\n
Oil fill<\/td>\nSynthetic PAO (cold climate)<\/td>\n<\/tr>\n
Output shaft<\/td>\nSolid or hollow bore<\/td>\n<\/tr>\n
Duty<\/td>\nS3 5\u201325%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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7. Barrier Gate and Security Gate Applications<\/h2>\n\n\n\n
\"NMRV<\/p>\n
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Car Park and Toll Boom Barrier<\/div>\n

High-cycle car park barriers performing 500 to 2,000 operations per day. NMRV 030 or 040 at 40:1 to 60:1, YS 0.06 to 0.18 kW, 2-pole or 4-pole. 2 to 3 second arm travel. S3 5% duty. Counterbalance spring offsets most of arm weight \u2014 motor only controls speed and acceleration. Self-locking holds arm down against wind uplift between operations without motor power.<\/p>\n<\/div>\n<\/td>\n

\"NMRV<\/p>\n
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Industrial Sliding Security Gate<\/div>\n

Factory perimeter and site access sliding gates from 3 to 10 m wide, 100 to 1,500 kg leaf weight. NMRV 050 to 075 at 40:1 to 80:1, Y2 0.25 to 1.5 kW. 10 to 30 second open time via rack-and-pinion or chain drive. Low cycle rate (10 to 50 ops\/day). Self-locking prevents forced entry when motor is de-energised. IP55 outdoor gearmotor with synthetic oil for all-weather reliability.<\/p>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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Rising Bollard Drive<\/div>\n

Security bollards rising 600 to 900 mm in 3 to 5 seconds. NMRV 040 or 050 at 60:1 to 80:1, YS 0.12 to 0.37 kW. Very high self-locking torque holds bollard against vehicle impact when de-energised. IP55 essential \u2014 below-grade installation exposed to water ingress. Stainless fasteners for corrosion resistance in wet pit.<\/p>\n<\/div>\n

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Airport Security Gate<\/div>\n

Airside perimeter security barriers with high-security forced entry resistance. NMRV 063 at 60:1 to 80:1, Y2 0.37 to 0.75 kW. 4 to 6 second arm travel. Obstacle detection safety edge mandatory. Motor sized for 2\u00d7 normal torque to handle safety reversal from closed against an obstacle. Self-locking prevents airside unauthorised passage when motor is off.<\/p>\n<\/div>\n

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Retractable Road Blocker<\/div>\n

Heavy vehicle blockers at government facilities, embassies, and critical infrastructure sites. Very high rated impact resistance (K12, K4 rating). NMRV 090 at 60:1 to 80:1, Y2 1.5 to 4.0 kW. Raise time 3 to 5 s. The NMRV self-locking torque combined with the mechanical blocker structure provides the rated vehicle impact resistance when the blocker is deployed.<\/p>\n<\/div>\n

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Swing Gate for Residential Estate<\/div>\n

Residential estate and commercial property swing gates from 2 to 5 m per leaf, 50 to 300 kg. NMRV 030 or 040 at 30:1 to 60:1, YS 0.06 to 0.25 kW. 10 to 20 second open time. Low cycle (20 to 100 ops\/day). Self-locking holds gate against wind loading and prevents casual manual forcing without actuator.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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\"Korea<\/p>\n

Worm Gear Machining<\/div>\n<\/div>\n
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\"Korea<\/p>\n

Self-Lock Torque Test<\/div>\n<\/div>\n
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\"Korea<\/p>\n

Stock Available<\/div>\n<\/div>\n
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\"Korea<\/p>\n

Global Export<\/div>\n<\/div>\n<\/div>\n

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8. Frequently Asked Questions<\/h2>\n
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How do I release a barrier gate manually if the motor fails and power is lost?<\/div>\n<\/div>\n
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Barrier gates with self-locking NMRV worm gearmotors require a manual release mechanism because the worm gear cannot be back-driven. There are two standard approaches: (1) a manual release lever on the gearmotor output shaft that disconnects the arm from the gearbox output, allowing the counterbalanced arm to be raised manually by hand \u2014 this is the most common approach on car park barriers where manual release for traffic flow during power failure is important; (2) a battery backup UPS that powers the barrier control board and motor during mains power failure, allowing the barrier to complete its current operation and open for emergency clearance. For security applications where the barrier must remain closed during power failure (fail-secure), the self-locking NMRV gearmotor with no manual release provides exactly this behaviour \u2014 the barrier stays locked in whatever position it is in when power fails, and cannot be opened until power is restored and the authorised access signal is received. Confirm the required fail-state (fail-safe open vs fail-secure closed) with the security consultant before specifying the barrier drive.<\/p>\n<\/div>\n<\/div>\n

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Why does my barrier gate motor overheat after a few hundred operations in a short period?<\/div>\n<\/div>\n
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Barrier motor overheating in high-cycle periods is almost always caused by operating the motor beyond its S3 rated duty cycle. At an average of 4 seconds motor-on time per operation (2 s open + 2 s close), the motor operates for 4 seconds out of every typical 30-second vehicle clearance cycle \u2014 approximately 13% CDF. A motor rated S3 10% would overheat at this rate; specify S3 15% or S3 25% depending on the actual cycle frequency. For ticketed car park barriers during peak hour with cars arriving every 15 seconds: 4 s on \/ 15 s cycle = 27% CDF \u2014 this requires an S3 25% or even S3 40% rated motor at the peak hourly rate. The thermal limit is usually reached in the NMRV gearbox oil before the motor winding \u2014 check whether the gearbox housing is hot to the touch (above 70\u00b0C) during high cycle periods; if so, the gearbox is undersized for the thermal duty and a larger NMRV size is required rather than changing the motor alone.<\/p>\n<\/div>\n<\/div>\n

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Can I use a VFD on a barrier gate motor to get a soft start and slow end to prevent arm bounce?<\/div>\n<\/div>\n
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Yes, and this is becoming standard practice on premium barrier systems. A VFD allows the barrier arm to accelerate gently from rest (preventing jerking that causes arm bounce and premature pivot bearing wear), travel at full speed in the mid-arc, and decelerate smoothly to a cushioned stop at the full open or closed position. This eliminates the mechanical end-of-travel buffers that standard barriers use to absorb the arm kinetic energy at the end of travel \u2014 buffers that wear and need periodic replacement. The VFD also allows the open and close speeds to be set independently, and can provide safety deceleration if an obstacle is detected in the arm path. For a barrier gate VFD installation, specify the YVF2 IC416 inverter-duty motor rather than the standard Y2, because the IC416 ensures full torque at the low speeds used during the deceleration phase of arm travel. The VFD and motor control cabinet is typically mounted in the barrier cabinet above the NMRV gearmotor, outside the weather exposure zone.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Korea Ever-Power \u00b7 NMRV Series \u00b7 Barrier Gate and Security Gate Gearmotors<\/div>\n

Need a Self-Locking Gearmotor for Your Barrier or Security Gate?<\/h2>\n

Korea Ever-Power NMRV: 30:1\u201380:1 self-locking ratios, NMRV 030\u2013090, IP55 outdoor, synthetic oil option, YS 0.06 kW to Y2 1.5 kW input, solid or hollow bore output.<\/p>\n

View NMRV Gearmotor Range<\/a><\/p>\n<\/div>\n<\/div>\n

Edited by Cxm<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

Korea Ever-Power \u00b7 NMRV Series \u00b7 Barrier Gate and Security Gate Drive Guide Worm Gear Motor for Barrier Gate and Security Gate: Self-Locking, Torque and Duty Cycle Selection Guide Barrier gates, security boom gates, sliding security gates, and rising bollards all share the same fundamental drive requirement: a motor gearbox that can lift, rotate, or […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[28],"tags":[],"class_list":["post-199","post","type-post","status-publish","format-standard","hentry","category-industrial-electric-motor"],"_links":{"self":[{"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/posts\/199","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/comments?post=199"}],"version-history":[{"count":1,"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/posts\/199\/revisions"}],"predecessor-version":[{"id":203,"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/posts\/199\/revisions\/203"}],"wp:attachment":[{"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/media?parent=199"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/categories?post=199"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/industrialelectricmotor.net\/fi\/wp-json\/wp\/v2\/tags?post=199"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}