Description
Key Features of Curtis 1221M-6701
1.Wide Voltage Range
The Curtis 1221M-6701 supports: – 48V – 60V – 72V – Maximum 80V application.For replacement or installation, always confirm against the vehicle’s actual battery voltage and controller configuration. Do not connect to different voltage systems merely based on model number.
2.550A High-Current Output Capacity
The 1221M-6701 delivers high traction current capability with the following current ratings: – 1-minute rated current: 550A – 5-minute rated current: 375A – 1-hour rated current: 225A. Accordingly, 550A is a short-time rating and not intended for unlimited continuous output.
Suitable for High-Power DC Series-Wound Motors
The 1221M-6701 is designed exclusively for DC Series Winding Motors. Recommended motor power range: 8.0-15.6 kW. Maximum motor power at 80V: 17.00 kW.
High-power control capability makes it ideal for: – Industrial forklifts – Material-handling vehicles – Electric industrial vehicles – Personnel carriers – Golf carts – Other high-power DC-powered electric vehicles.
15.6 kHz High-Frequency PWM Control
The 1221M-6701 operates at 15.6 kHz PWM. High-frequency switching technology combined with ultra-low voltage drop design delivers: – High operating efficiency – Smooth speed regulation -Low operating noise – Improved motor torque control.For electric vehicles with frequent acceleration, deceleration and state changes, high-frequency PWM enables refined motor control.
Programmable Control
Programmability is one of the standout features of the Curtis 1221M series. Use the following tools for parameter adjustment, fault diagnosis and system testing: – Curtis 1313-4331 Handheld Programmer – Curtis 1314 PC Programming Station.
Controller parameters can be tuned to match individual vehicle conditions for flexible vehicle behaviour. This is especially valuable for vehicle retrofits, controller replacements and compatibility with diverse motor systems.
Multi-Throttle Compatibility
The 1221M-6701 supports multiple throttle input types: – 0-5kΩ – 5kΩ-0 – 0-5V.
Throttle Fault Protection
Dedicated throttle-fault protection circuitry is implemented. In the event of open-circuit or other throttle-line abnormalities, the controller disables output to reduce risks of unintended vehicle movement caused by throttle faults.It also features High Pedal Disable. If throttle input is already active when vehicle key-on occurs, vehicle operation is inhibited. This minimises risk of unexpected startup upon power-on.
Plug Braking Function
The 1221M-6701 supports Plug Braking with an integrated plug-brake diode inside the controller. Plug braking provides controllable braking performance during vehicle deceleration and direction reversal.
Thermal Protection and Thermal Compensation
Thermal-protection and compensation circuitry maintains constant current limiting across the full operating temperature range and during high/low-temperature derating, preventing abrupt power loss caused by temperature variation. This is particularly critical for industrial vehicles, where controllers may generate substantial heat under heavy loads, prolonged operation or high ambient temperatures.
Undervoltage Protection
Undervoltage derating is available. When battery voltage drops excessively (including voltage drop caused by external loads), the controller limits output to protect both battery and controller system. This prevents high-load operation with insufficient battery voltage.
Rugged Aluminium Enclosure
The 1221M series adopts extruded anodised-aluminium enclosure with IP65 environmental sealing rating. The construction provides robust mechanical and environmental protection for internal electronics, well-suited for industrial-vehicle operating conditions.
Note: Different vendor listings may feature different versions or assembly configurations. Refer to product specifications supplied by your specific supplier at the time of procurement.
Simplified Power and Control Connections
User-friendly connection design for the 1221M-6701: – Plug-in connectors for control-signal wiring – Plated solid-copper busbars for power connections – Clear-labelled motor connection terminals.This simplifies installation and maintenance work.
Complete 1221M-6701 Controller Assembly
The full assembly includes: – Curtis 1221M-6701 controller – Main contactor – Forward / Reverse contactors – Power-circuit fuse – Control-circuit fuse – Wiring harness – Matching connectors – Aluminium heat-dissipation mounting plate – Foot accelerator – Coil suppression diodes – Pre-charge resistor – Mounting bolts, washers and nuts.The complete assembly is recommended for users requiring a full motor-control system rather than only a standalone controller replacement.
Installation Convenience
Major components of the 1221M-6701 controller assembly are pre-mounted on the aluminium heat-dissipation plate, supplied with plug-in connectors and mounting hardware. Available supporting documentation: – 1221M controller connector pin-out definitions – 1221M-6701 assembly installation instructions – 1221M-series user manual -Controller wiring diagrams.
For users without controller-installation experience, consultation with vehicle / motor dealers is recommended prior to installation.
J5 Terminal Description
The J5 terminal is disabled by factory default. To utilise J5 functions: -Rev Input -Main Driver.Follow procedures documented in the 1204M / 1205M / 1221M controller manual. For replacement or retrofit projects, do not wire purely based on physical appearance or terminal layout. Always cross-reference wiring diagrams and original vehicle configuration.
Technical Specifications
| Parameter | Curtis 1221M-6701 Specifications |
| Model Number | 1221M-6701 |
| Controller Type | Programmable DC Series-Wound Motor Controller |
| Nominal Battery Voltage | 48V / 60V / 72V (80V max) |
| Default Voltage Setting | 72V (FridayParts reference) |
| 1-Minute Rated Current | 550A |
| 2-Minute Rated Current | 550A (YEM / FridayParts title & specification) |
| 5-Minute Rated Current | 375A |
| 1-Hour Rated Current | 225A |
| PWM Frequency | 15.6 kHz |
| Plug Braking | Supported, A2 Busbar |
| Recommended Motor Power Range | 8.0-15.6 kW |
| Max Motor Power @ 80V | 17.00 kW |
| Minimum Electrical Isolation | 500 VAC |
| KSI Input Current | 70 mA (no programmer) / 130 mA (programmer connected) |
| Logic Input Current | < 2 mA |
| Status-LED Output Current | < 2 mA |
| Default Throttle | 0-5kΩ |
| Other Supported Throttles | 5kΩ-0, 0-5V |
| Operating Ambient Temperature | -40 °C to 50 °C |
| Storage Temperature | -40 °C to 85 °C |
| Electronics Ingress Protection | IP65 (NOCO reference) / IP54 (FridayParts sales version) |
| Programming Tools | Curtis 1313-4331 / 1314 |
| Assembly Net Weight | 13.4 kg |
| Assembly Shipping Weight | 15.8 kg |
Typical Application Scope
1.Industrial Vehicles
The 1221M series delivers speed-and-torque control for high-power DC series-wound motors across a wide range of industrial vehicles.
2.Material-Handling Vehicles
Suitable for material-handling equipment requiring high traction current and precise speed regulation.
3.Electric Forklifts
High-550A current rating plus plug-braking, undervoltage and thermal-protection features suit certain electric-forklift traction systems. Always verify vehicle voltage, motor type and original controller model before replacement.
4.Golf Carts
Golf carts are listed among target vehicle types for the 1221M series.
5.Personnel Carriers
Personnel carriers represent another typical application scenario.
6.Other High-Power Electric Vehicles
Also a candidate selection for electric vehicles fitted with DC series-wound motors requiring 48V-72V (or higher) operating voltage and large startup current.
Cross-Reference Part Numbers
Interchangeable / cross-reference part-number variants: – 1221M-6701 – 1221M-67 01 -1221M6701
When ordering replacement units, provide the full part number 1221M-6701 to avoid misidentification caused by formatting differences.
Procurement & Installation Guidelines
1.Confirm Battery Voltage
Verify whether the vehicle operates on a 48V, 60V or 72V system prior to purchase. For 80V-rated applications, double-check exact controller version and motor power rating.
2.Confirm Motor Type
The 1221M-6701 is built for DC series-wound motors. Select alternative controllers for AC induction motors, permanent-magnet motors or other motor types.
3.Confirm Motor Power
Recommended motor-power range: 8.0-15.6 kW; maximum 17 kW at 80V. Final selection shall also consider motor name-plate ratings and vehicle load conditions.
4.Confirm Throttle Type
Factory default: 0-5kΩ potentiometer throttle. Confirm correct parameter setup if original vehicle uses 0-5V or 5kΩ-0 throttle hardware.
5.Confirm Controller Form Factor
Both standalone controllers and complete assemblies (including contactors, fuses, throttle, harness and mounting plate) are available on the market. Specify your required form before placing orders.
6.Confirm Wiring
Do not wire based purely on physical appearance of the old controller. Validate against formal wiring diagrams for: – Battery connections – Motor connections -Main contactor – Forward / Reverse contactors – Throttle – KSI – J5 terminal – Fuses – Pre-charge circuit
FAQ
Q1: What is the Curtis 1221M-6701?
A: The Curtis 1221M-6701 is a programmable DC series-wound motor controller. It governs speed and torque for high-power DC series-wound motors and is used on industrial vehicles, material-handling vehicles, personnel carriers, golf carts and more.
Q2: What voltage does the 1221M-6701 support?
A: It supports 48V, 60V, 72V with maximum 80V capability. FridayParts lists 72V as the factory-default setting with 48V / 60V as configurable options. Confirm exact hardware version at procurement.
Q3: What is the current rating of the 1221M-6701?
A: Maximum short-time rated current is 550A. Additional ratings: 375A for 5-minute duty cycle, 225A for 1-hour duty cycle. 550A is not a continuous unrestricted operating current.
Q4: What throttle types are supported?
A: Supported throttle inputs: 0-5kΩ, 5kΩ-0 and 0-5V. NOCO EVCO supplied assemblies use 2-wire 0-5kΩ potentiometer throttle EFP-001 as standard.
Q5: Is the 1221M-6701 programmable?
A: Yes. Compatible with Curtis 1313-4331 handheld programmer and Curtis 1314 PC programming station for parameter setup, diagnosis and testing.
Q6: Does the 1221M-6701 support plug braking?
A: Yes. Plug Braking (A2 Busbar) is supported, with plug-brake diode integrated inside the controller.
Q7: What size motor is the 1221M-6701 suitable for?
A: Recommended motor-power range: 8.0-15.6 kW; maximum 17.00 kW at 80V. Application selection shall also account for motor nominal parameters and vehicle load.
Q8: Can the 1221M-6701 directly replace other Curtis controllers?
A: Direct drop-in replacement cannot be assumed based only on appearance. Although the 1221M series upgrades 1209, 1209B and 1221 platforms, verify voltage, motor type, current rating, throttle type, wiring, contactor hardware and programmed parameters. If purchasing a full assembly, confirm vehicle compatibility with supplied contactors, fuses and throttle hardware.
Summary
The Curtis 1221M-6701 Controller is a high-current programmable DC series-wound motor controller. Core specifications: 48V/60V/72V (max 80V), 550A short-time rated current, 375A 5-minute rating and 225A 1-hour rating. It adopts 15.6 kHz high-frequency PWM control and integrates plug braking, undervoltage protection, thermal protection, throttle-fault protection and High Pedal Disable.
For commissioning and maintenance, it works with Curtis 1313-4331 and 1314 programming tools to enable parameter configuration and fault diagnosis for diverse vehicle requirements. Its anodised-aluminium enclosure, solid-copper power busbars and plug in control connectors make it well-adapted to industrial-vehicle environments.
Wiring Diagram:
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