PTC Thermistor MZ3-B-47ROM Motor Starter 47Ω 300VAC for Refrigerator Air Conditioner Compressor
Price:
Negotiable
MOQ:
1000
Delivery Time:
1-2 weeks
Brand:
AFTPTC
Product Description
Refrigerators Frequency Converters Motor Overheat Protection PTC Thermistor MZ3-B-47ROM
PTC Thermistor MZ3-B-47ROM designed for motor starter applications in air conditioners, refrigerators, and frequency converters, providing reliable overheat protection and motor starting assistance.
Key Advantages
- Economical, reliable, and simple circuit design
- Contactless operation with low noise
- High reliability and long service life
- Outperforms traditional hammer-type starting circuits
Motor Start-up PTC Thermistor Description
Positive temperature coefficient thermistors for motor starting are primarily used in refrigerators, air conditioners, frequency converters, and motor overheat protection systems.
Working Principle
The motor starter utilizes the current-time characteristic of PTC ceramic. When voltage is applied, a large current flows through the PTCR. As temperature rises, resistance increases rapidly, causing current to drop sharply. This delay period (0.1 seconds to several seconds) depends on heat capacity, resistance value, heat dissipation conditions, load resistance, and working voltage.
When starting, motors require large current and torque to overcome inertia and load reaction forces. A PTC thermistor connected in series with the starting auxiliary coil provides initial low resistance for startup, then switches to high resistance to cut off the auxiliary coil once normal operation is achieved.
Important Note: Allow sufficient recovery time (tr) between operations for the PTCR to return to original temperature state. Immediate repetitive actions should be avoided to prevent compressor failure.
MZ3-B-47ROM Specifications
| Parameter | Value |
|---|---|
| Operating Temperature | -20°C to +85°C |
| Maximum Voltage/Current | 300VAC/50HZ, 7A |
| Initial Resistance | R25=47Ω±25% |
| Switching Temperature | TC25=130±10℃ |
| Withstand Voltage | VE=500V, T=3min |
| Power Consumption | ≤3.0W, Vd=250V |
PTC Thermistor Motor Starter Overview
PTC Thermistor Motor Starters delay switch-off of motor starter auxiliary winding after motor acceleration to protect windings from damage. These solid-state devices provide economical torque assist for heat pumps, air conditioning, and refrigeration systems.
When circuit is turned on, PTC has low resistance with most line voltage applied to starter winding. After starting, PTC heats up and switches to high resistance state. Current through starter winding decreases substantially once motor winding temperature reaches PTC trip temperature.
Benefits vs Traditional Systems
- Saves wiring connections
- Occupies less panel space
- Easier mounting
- Lower cost compared to start capacitor and relay systems
Applications
- Single-phase motor start assist in refrigerator systems
- Air-conditioning systems and heat pumps
- Small compressors
- Inrush current generation
Product Features
- Complete range of size resistance combinations for 120V, 240V compressor motors
- Rugged silver electrodes for long life pressure contact mounting
- Various pellet sizes for optimum inrush current and switching time
- Typical resistance values: 4.7Ω, 6.8Ω, 15Ω, 22Ω, 33Ω, 47Ω
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Get in Touch
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Company
Dongguan Ampfort Electronics Co., Ltd.
Location
Floor 5,Changlong Industrial Building,No.6,Jiangnan Road,Jingshan,Chashan Town,Dongguan 523323,China
Contact Person
James Lai