INOMAX MAX500 Series – Versatile AC Drive for Pumps, Fans, Conveyors & Industrial Automation
1. Overview – A Reliable Variable Frequency Drive for General Purpose Applications
The INOMAX MAX500 series is a high‑performance variable frequency drive (VFD) designed for general purpose industrial applications. Whether you need an AC drive for a water pump, a VSD (variable speed drive) for a conveyor belt, or a frequency inverter for a fan or compressor, the MAX500 delivers outstanding value without compromising on quality or reliability.
Unlike expensive European brands, this adjustable speed drive offers European‑level performance at a highly competitive price. It is the ideal frequency converter for motor control in applications such as pumps, fans, conveyors, mixers, extruders, HVAC systems, woodworking machines, textile equipment, and agricultural irrigation. As a micro drive or vector drive, the MAX500 supports sensorless vector control (SVC), V/F control, and closed‑loop vector (VC) with an optional encoder card.
Built by INOMAX – a trusted industrial frequency drive manufacturer with automated German SMT lines, 100% full‑load motor testing, and an annual defect rate below 1% – the MAX500 provides a cost‑effective AC frequency converter for motor that meets the needs of distributors, OEMs, panel builders, and project integrators worldwide.
Key benefits of this variable speed drive for 3 phase motor:
✅ Control modes: V/F, sensorless vector (SVC), closed‑loop vector (VC) – versatile for any load
✅ Starting torque: 150% @ 0.5Hz (SVC), 200% @ 0Hz (VC) – reliable starting for heavy machinery
✅ Overload capacity: 150% for 60s, 180% for 10s, 200% for 1s – handles short‑term peaks
✅ Output frequency: up to 600Hz (V/F) – suitable for high‑speed spindles
✅ Built‑in functions: PID, multi‑pump control (up to 4 pumps), sleep/wake, simple PLC, energy optimizer
✅ Enclosure: IP20 standard, IP21/IP54 optional – indoor or protected outdoor use
✅ Power range: 0.4kW – 630kW (wall‑mounted up to 110kW, cabinet above)
✅ Voltage: 1‑phase/3‑phase 200‑240V, 3‑phase 380‑480V, and 525‑690V on request
2. Core Technology – Sensorless Vector Control & V/F Modes for Reliable Motor Control
The INOMAX MAX500 variable frequency drive offers three control modes to match any application. This AC drive can operate as a VSD (variable speed drive) for pumps, a frequency inverter for fans, or an adjustable speed drive for conveyors.
| Feature | Specification | Benefit for Your Application |
|---|---|---|
| Control modes | V/F, Sensorless Vector (SVC), Closed‑loop Vector (VC with PG card) | One inverter for AC motor covers all common industrial loads |
| Starting torque (SVC) | 150% @ 0.5Hz | Reliable start for heavy‑duty pumps, mixers, and crushers |
| Starting torque (VC) | 200% @ 0Hz | High precision for positioning applications |
| Speed range | 1:100 (V/F), 1:200 (SVC), 1:1000 (VC) | Wide speed regulation without gears |
| Speed accuracy | ±0.5% (V/F), ±0.2% (SVC), ±0.02% (VC) | Consistent process control |
| Overload capacity | 150% for 60s, 180% for 10s, 200% for 1s | Handles temporary overloads without tripping |
| Output frequency | 0 – 600Hz (V/F mode) | Suitable for high‑speed spindles (woodworking, CNC) |
| Carrier frequency | 1 – 12kHz adjustable | Balances motor noise and drive loss |
This low voltage AC drive is available as a single phase input AC drive (0.4‑5.5kW) or 3 phase variable frequency drive (0.4‑630kW), making it the perfect speed controller for 3 phase motor in factories, farms, and commercial buildings.
3. Key Advantages – Solving Everyday Industrial Pain Points with a Versatile VSD
| Pain Point | MAX500 Solution | Benefit to Customer |
|---|---|---|
| Budget constraints but need decent quality | Full quality testing at competitive price | Lower initial cost without reliability risk |
| Complex commissioning for simple applications | User‑friendly keypad with quick parameter copy | Reduced training and commissioning time (hours to minutes) |
| Multiple motor types and load profiles | V/F, SVC, VC modes + built‑in PID, multi‑pump, sleep/wake | One frequency converter for fans, pumps, conveyors, compressors, mixers |
| Dusty or humid environment | Conformal coating as standard, independent air duct design | Longer service life (5‑8 years typical) |
| High energy cost for pumps & fans | Built‑in energy optimizer, PID, multi‑pump alternation | Typical 20‑40% energy savings |
| After‑sales support concerns | 24 months warranty, global technical support, fast spare parts | Peace of mind for distributors and end users |
4. Industry Solutions – Real‑World Applications of This Adjustable Speed Drive
The MAX500 variable speed drive has been deployed across 40+ countries in water treatment, irrigation, manufacturing, and building automation. Below are representative projects (customer names desensitized).
4.1 Water Supply & Wastewater Treatment – VFD for Water Pump
| Region | Application | Power | Model | Quantity | Highlights |
|---|---|---|---|---|---|
| Morocco | Seawater desalination | 75‑400kW | Various | 70 units | Energy savings >25% |
| Chile | Municipal water distribution | 15‑250kW | Various | 120 units | Multi‑pump alternation saved 32% energy |
| Tunisia | Wastewater treatment | 5.5‑160kW | Various | 2,500 units | Largest single project; MTBF >80,000 hrs |
| Russia | Urban water supply | 2.2‑315kW | Various | 320 units | Operates at -30°C with conformal coating |
4.2 Agricultural Irrigation – AC Drive for Irrigation System & Submersible Pump
| Region | Application | Power | Model | Quantity | Highlights |
|---|---|---|---|---|---|
| Iraq | Deep well (300m) | 11‑90kW | Various | 60 units | Dry‑run protection standard |
| Turkey | Pressurized irrigation | 2.2‑110kW | Various | 1,200 units | Multi‑pump alternation |
| Egypt | Nile delta sprinkler | 1.5‑250kW | Various | 500+ units | Energy savings >25% vs star‑delta |
| Peru | Andean highland irrigation | 1.5‑110kW | Various | 220 units | Altitude 3,500m with derating |
4.3 Industrial Manufacturing – Frequency Inverter for Extruder & Conveyor
| Region | Application | Power | Model | Quantity | Highlights |
|---|---|---|---|---|---|
| China | CNC routers & high‑speed spindles | 5.5‑75kW | Various | 150+ units | 600Hz output (24,000 RPM), 0.5% accuracy |
| China | Textile spinning & winding | 4‑90kW | Various | 200+ units | Swing frequency reduced yarn breakage 18% |
| Turkey | Food processing conveyors | 1.5‑75kW | Various | 350+ units | IP54 wash‑down optional |
4.4 HVAC & Building Automation – Variable Speed Drive for Cooling Tower Fan
| Region | Application | Power | Model | Quantity | Highlights |
|---|---|---|---|---|---|
| Ecuador | Commercial building HVAC | 2.2‑160kW | Various | 181 units | Integrated with BMS; energy savings 28% |
| Russia | District heating pumps | 0.75‑90kW | Various | 400 units | Outdoor installation at -35°C |
| Indonesia | Hotel & mall HVAC | 5.5‑22kW | Various | 500 units | Compact R1‑R3 fit into existing MCC |
Global summary: 15,000+ units in China, 1,500+ in Russia/CIS, 1,200+ in Southeast Asia, 800+ in South America, 400+ in Africa.
5. Complete Model Range – 0.4kW to 630kW, Single Phase & 3 Phase Input
The MAX500 variable frequency drive is available in multiple configurations to suit your motor and power supply.
Model naming: MAX500-{PowerCode}-{VoltageCode}B
-
Voltage codes:
2B= 200‑240V 1‑phase input,3B= 380‑480V 3‑phase input -
Power codes:
0R4= 0.4kW,1R5= 1.5kW,002= 2.2kW,004= 4.0kW, etc.
| Power (kW) | MAX500 Model (3‑phase 380‑480V) | Rated Current (A) | Frame | Built‑in Brake Unit | Application Example |
|---|---|---|---|---|---|
| 0.4 | MAX500-0R4-3B | 1.2 | R1 | Standard (≤30kW) | Small fan, lab equipment |
| 0.75 | MAX500-0R75-3B | 2.4 | R1 | Standard | Small pump, conveyor |
| 1.5 | MAX500-1R5-3B | 3.7 | R1 | Standard | Mixer, agitator |
| 2.2 | MAX500-2R2-3B | 5.0 | R1 | Standard | Small compressor |
| 4.0 | MAX500-004-3B | 9.5 | R2 | Standard | Industrial fan |
| 5.5 | MAX500-5R5-3B | 12.5 | R2 | Standard | Centrifugal pump |
| 7.5 | MAX500-7R5-3B | 17.0 | R2 | Standard | Small HVAC system |
| 11 | MAX500-011-3B | 25.0 | R3 | Standard | Booster pump |
| 15 | MAX500-015-3B | 32.0 | R3 | Standard | Cooling tower fan |
| 18.5 | MAX500-018-3B | 38.0 | R3 | Standard | Woodworking spindle |
| 22 | MAX500-022-3B | 45.0 | R3 | Standard | Textile machine |
| 30 | MAX500-030-3B | 61.0 | R4 | Optional | Large fan, kneader |
| 37 | MAX500-037-3B | 72.0 | R4 | Optional | Centrifugal compressor |
| 45 | MAX500-045-3B | 87.0 | R5 | Optional | Plastic extruder |
| 55 | MAX500-055-3B | 105.0 | R5 | Optional | Industrial mixer |
| 75 | MAX500-075-3B | 145.0 | R6 | Optional | Large irrigation pump |
| 90 | MAX500-090-3B | 169.0 | R6 | Optional | Wastewater pump |
| 110 | MAX500-110-3B | 206.0 | R7 | Optional | Hydraulic system |
| 132 | MAX500-132-3B | 246.0 | R7 | Optional | Chiller, large compressor |
| 160 | MAX500-160-3B | 293.0 | R8 | External | Mining conveyor |
| 200 | MAX500-200-3B | 363.0 | R8 | External | Industrial fan (steel plant) |
| 250 | MAX500-250-3B | 430.0 | R8 | External | Water supply station |
| 280 | MAX500-280-3B | 487.0 | R8 | External | Large HVAC system |
| 315 | MAX500-315-3B | 546.0 | R9 (cabinet) | External | Desalination pump |
| 355 | MAX500-355-3B | 624.0 | R9 (cabinet) | External | Cement separator |
| 400 | MAX500-400-3B | 760.0 | R9 (cabinet) | External | Mining fan |
| 450 | MAX500-450-3B | 865.0 | R9 (cabinet) | External | Large water pump |
| 500 | MAX500-500-3B | 950.0 | R9 (cabinet) | External | Industrial mixer |
| 560 | MAX500-560-3B | 1050.0 | R9 (cabinet) | External | Petrochemical pump |
| 630 | MAX500-630-3B | 1140.0 | R9 (cabinet) | External | Large conveyor, ball mill |
Single‑phase input models (220V): Available from 0.4kW to 5.5kW (e.g., MAX500-0R4-2B, MAX500-1R5-2B, MAX500-1002-2B). These single phase input AC drives are ideal for farms and small workshops where three‑phase power is unavailable.
6. Direct Replacement for Competitor Variable Frequency Drives
The MAX500 frequency inverter is designed to directly replace popular AC drives from INVT, Veichi, LS, Delta, Danfoss, and Schneider without panel modification. Below is a partial cross‑reference.
| Competitor | Model | MAX500 Equivalent | Power (kW) | Notes |
|---|---|---|---|---|
| INVT | GD20‑004G‑4 | MAX500-004-3B | 4.0 | Same footprint, terminal mapping |
| INVT | GD20‑7R5G‑4 | MAX500-7R5-3B | 7.5 | |
| INVT | GD20‑022G‑4 | MAX500-022-3B | 22 | |
| INVT | GD20‑200G‑4 | MAX500-200-3B | 200 | External brake unit |
| Veichi | S100‑2R2‑3B | MAX500-2R2-3B | 2.2 | Identical I/O |
| Veichi | S100‑015‑3B | MAX500-015-3B | 15 | |
| Veichi | S100‑200‑3B | MAX500-200-3B | 200 | |
| LS | iG5A‑4 | MAX500-004-3B | 4.0 | LS has lower overload |
| LS | iS7‑030‑4 | MAX500-030-3B | 30 | |
| Delta | VFD007M43B | MAX500-7R5-3B | 7.5 | |
| Delta | VFD022M43B | MAX500-022-3B | 22 | |
| Danfoss | FC‑051P7K5T4E20H1 | MAX500-7R5-3B | 7.5 | Danfoss lacks conformal coating |
| Danfoss | FC‑101P22KT4E20H1 | MAX500-022-3B | 22 | |
| Schneider | ATV12H075M3 | MAX500-0R75-3B | 0.75 |
For any model not listed, contact us with your competitor’s exact part number – we will provide a cross‑reference within 24 hours. Our free PC tool (DriveStudio) can convert competitor parameter files to MAX500 format, reducing migration time to under 30 minutes.
7. Quality Assurance – Every Variable Frequency Drive Is 100% Full‑Load Tested
Every MAX500 AC drive undergoes the same strict quality process as our premium ACS880 series:
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Automated SMT lines (German equipment) – consistent quality
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Hardware 100% inspection – no missing components, loose terminals
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Functional 100% test – every I/O, protection parameter tested with a real motor (not simulation)
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Burn‑in test – 2 hours at rated load before packing
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Conformal coating as standard – 4 layers of German Bectron resin for moisture and dust resistance
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IP54 optional – for dusty and humid environments
Result: Annual defect rate <1%, typical lifespan >8 years. 24‑month warranty.
8. Troubleshooting & Common Pain Points – FAQ for Engineers and Distributors
Below are answers to the most frequently asked troubleshooting questions about variable frequency drives. These cover common pain point keywords that engineers search for when experiencing issues with VFDs, AC drives, or frequency inverters.
Q1: My variable frequency drive keeps tripping on overvoltage – what could be the cause?
Overvoltage trips usually occur during deceleration when the motor regenerates power back to the drive. Increase the deceleration time (parameter P1411) or add a braking resistor. If the AC drive is used in a lifting application, consider a regenerative unit. The MAX500 records the DC bus voltage in parameter P0100 to help diagnose.
Q2: The AC drive shows a ground fault error – how to fix it?
A ground fault (code GF) indicates leakage current between the motor windings and earth. Check motor insulation with a megger. If the motor is fine, the drive’s internal ground fault detection may be too sensitive – you can adjust the protection level via parameter P1324. For temporary troubleshooting, disconnect the motor and run the VFD without load to isolate the issue.
Q3: My VSD runs but the motor is not turning – what should I check?
First, verify that the drive output voltage is present (measure U, V, W). If voltage is normal, the motor may be stuck or wiring is loose. If the VSD is in sensorless vector mode but the motor is not connected, the drive will trip on output phase loss. Also check that the start command is active (parameter P1031 bit 4 should be 1). This is a common AC drive motor running rough or not turning problem.
Q4: How to reset a frequency inverter after an overload trip?
Press the STOP/RST button on the keypad, or cycle input power. The MAX500 stores the last 5 fault codes in parameters P1044 (current fault) and P1045 (previous faults). If overload trips repeat, increase the acceleration time (P1410) or check if the motor is mechanically jammed. For high‑inertia loads like centrifuges, enable the energy optimizer.
Q5: Why does my adjustable speed drive overheat?
Overheating (code OH2) is often caused by insufficient cooling – check that the cooling fan is running, the air inlet is not blocked, and the ambient temperature is below 40°C. The MAX500 has a temperature sensor on the heatsink (parameter P0107). If the drive is installed in a closed cabinet, add cabinet ventilation. Conformal coating is standard, but for very dusty environments, order the IP54 option.
Q6: How to fix a VFD that lost its program after a power outage?
The MAX500 saves parameters to non‑volatile memory automatically. If parameters are lost, the internal battery (if present) or capacitor may have failed. Always keep a backup of your parameters (upload to keypad or PC tool). To restore, download the saved file or manually re‑enter settings. This is a known issue with some cheap frequency inverters – our drives use high‑grade memory components.
Q7: Why does the frequency inverter show a communication error with the PLC?
Communication errors (code COM) can be caused by incorrect baud rate, wrong node address, poor shielding, or long cable runs. For Modbus RTU, use twisted‑pair shielded cable and keep the total length under 1000m. The MAX500 supports Modbus RTU as standard; Profibus‑DP is optional. Monitor receive counters via parameter P5040 to see if frames are being received.
Q8: How to solve output voltage unbalance in a variable frequency drive?
Unbalanced output voltage can be caused by a faulty IGBT module or poor connections. First, measure input voltage to the drive – if input is balanced, the problem is likely inside the drive. The MAX500 has individual phase current monitoring (parameters P1262‑P1264). If one phase current is significantly lower, contact support for repair or replacement under warranty.
Q9: My AC drive motor vibrates at low speed – what tuning is needed?
Low‑speed vibration is common in sensorless vector control when the motor parameters are not correctly identified. Perform motor auto‑tuning (parameter P1252 = 1 for rotating tuning, or 2 for static). Also, increase the carrier frequency (P0160) to reduce torque ripple. For very low speed (<5Hz) applications, enable the “high‑frequency injection” feature (P1337) if available, or add an encoder for closed‑loop control.
Q10: Can a lightning strike damage my VSD? How to protect it?
Yes, lightning can damage the input rectifier and control board. Install surge arrestors on the input power line and ensure proper grounding. The MAX500 has built‑in varistors, but external surge protection is recommended for outdoor or long cable runs. If the drive is damaged by lightning, our warranty covers manufacturing defects, not external acts of nature – but we offer reduced‑cost repairs.
Q11: What does error code “SC” mean on the MAX500?
SC stands for output short circuit (between phases or phase to ground). Immediately disconnect the motor and check wiring. If the motor cable is damaged or the motor windings are shorted, replace them. If the SC fault appears even without motor connected, the IGBT module may be defective – contact your distributor for service.
Q12: How to fix a frequency inverter that shows “display blank but power on”?
First, check the keypad cable connection (RJ45). If the cable is fine, the control board may have lost power or a component failed. The MAX500’s control board has a separate power supply; measure the +24V aux output. If no voltage, the internal power supply module may be faulty. Replace the control board or contact support.
Q13: Why does my AC drive blow fuses repeatedly?
Repeated fuse blowing indicates a hard electrical fault – typically a shorted IGBT or diode bridge. Disconnect power and measure resistance between input terminals (R/S/T) and DC bus (+/‑). Low resistance indicates a failed rectifier. The MAX500 has built‑in fast‑acting fuses to protect the rest of the system. Replace both the drive and check the motor for ground faults.
Q14: How to reset a frequency inverter after a “DC bus low” error?
DC bus low (code 23) means the input voltage dropped below the minimum (around 400V for 380V models). Check the supply voltage and input contactor. If the voltage is stable but the error persists, the drive’s undervoltage detection threshold may need adjustment (parameter P0163). For power loss ride‑through applications, enable the undervoltage suppression (P1330).
Q15: Why does the variable speed drive hum or make weird noises when idle?
The MAX500 uses PWM switching frequency (default 4kHz). A high‑pitched noise is normal. Reduce the carrier frequency (P0160) to lower the noise, but note that this increases motor audible noise. If the drive makes a clicking or sparking sound, there may be a loose connection or failing IGBT – power off and inspect.
Q16: How to troubleshoot VFD interference with other equipment?
RF interference is common when motor cables are unshielded or grounding is poor. Use shielded motor cable, ground the shield at both ends, and install ferrite cores. The MAX500 has a built‑in EMC filter (C3 class) – if interference persists, disconnect the internal filter screw (for IT systems) or add an external input filter.
Q17: My AC drive slows down randomly under load – why?
If the drive reduces speed without a command, it may be entering current limit or torque limit. Check parameter P1300 (forward torque limit) and P1301 (reverse torque limit). Also monitor the output current (P1002) and DC bus voltage (P0100). If current exceeds the drive rating, the MAX500 automatically folds back speed to protect itself – this is normal, but indicates the drive is undersized for the load.
Q18: The frequency inverter shows “E‑CAN” error – what does that mean?
E‑CAN indicates a communication error between the control board and power module. This can be caused by electromagnetic interference, loose ribbon cable, or hardware failure. Try resetting the drive. If the error recurs, contact technical support – the drive may need a new control board.
Q19: How to fix a variable frequency drive that cannot adjust speed anymore?
If the drive runs but speed command has no effect, check the speed reference source (parameter P1392). It may be set to a fixed value (e.g., keypad) instead of analog input or communication. Also verify that the drive is not in “local” mode (LOC displayed) – press LO/RE to switch to remote (REM). For PID control, the output may be limited by the PID settings.
Q20: Why does my VFD trip on phase loss (code 17) when the motor is fine?
Phase loss detection can be triggered by a loose terminal, a blown fuse, or an unbalanced supply. Measure input voltage at the drive terminals. If input is fine, the drive’s output phase loss detection may be too sensitive for light loads – you can increase the detection delay via parameter P0303 or P0304. For permanent magnet motors, disable phase loss detection during auto‑tuning.
Q21: How to recover a VSD after a firmware update failure?
If the firmware update was interrupted, the drive may not boot. The MAX500 has a bootloader that allows recovery via the serial port and our PC tool. Contact support with the drive model – we will provide a recovery image. Never power off during a firmware update.
Q22: What is the typical lifespan of an AC drive capacitor and how to extend it?
Electrolytic capacitors age with temperature and operating hours. The MAX500 uses high‑grade capacitors rated for 85°C. To extend life, keep the drive ambient temperature below 40°C, avoid long storage without power (reform capacitors every 2 years), and ensure clean power without high harmonics. Capacitor life is typically 8‑10 years.
Q23: Can I use a single‑phase variable frequency drive to run a three‑phase pump?
Yes. The MAX500 single‑phase input models (e.g., MAX500-1R5-2B) accept 220V single‑phase and output 220V three‑phase. This is a cost‑effective solution for farms and rural areas without three‑phase utility. Ensure the motor is rated for 220V delta connection. Do not exceed 5.5kW for single‑phase input.
Q24: How to program the MAX500 for constant pressure water supply with PID?
Set parameter P1392 = P0147 (AI1 feedback), P0725 = 1 (PID enable), and adjust P0726 (proportional gain) and P0727 (integral time). The setpoint comes from an external pressure sensor (4‑20mA or 0‑10V). The MAX500 will then vary pump speed to maintain constant pressure. Multi‑pump alternation can be enabled via P28.02‑P28.03.
Q25: Where to download the MAX500 user manual and PC configuration tool?
All manuals, datasheets, and the free DriveStudio PC tool are available on our website: www.inomaxtechnology.com/downloads. The PC tool supports parameter backup, real‑time monitoring, and firmware updates.
9. Optional Accessories
| Accessory | Part Number | Description |
|---|---|---|
| Output reactor | OCL‑xxx‑A/L | For motor cable >100m, reduces harmonics |
| IP54 enclosure kit | ENC‑IP54 | For wall‑mount models in dusty environments |
| Braking resistor | BR‑MAX500‑xxx | For high‑inertia loads (e.g., centrifuges) |
| PG card (incremental encoder) | PG‑INC‑MAX500 | Enables closed‑loop vector control (VC) |
| PG card (resolver) | PG‑RES‑MAX500 | For resolver feedback |
10. Contact Us – Get Factory Prices for Variable Frequency Drives
Looking for a reliable, cost‑effective variable frequency drive for your project or distribution? As a direct manufacturer, we offer competitive pricing, fast delivery, and full technical support.
Email: info@inomaxtechnology.com
WhatsApp/WeChat: +86 150 1853 9591
Website: www.inomaxtechnology.com
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